Method and apparatus for partial retransmission in wireless cellular communication system

ABSTRACT

A communication method and system are provided for converging a 5G communication system with IoT technology. A method by a terminal includes receiving information on a number of CBGs of a TB via higher layer signaling; identifying the number of the CBGs of the TB based on the information; receiving DCI scheduling downlink data transmission, wherein the DCI includes an NDI and a CBG indicator; receiving downlink data corresponding to the TB; in case of identifying that the DCI is associated with an initial transmission of the TB based on the NDI, identifying the CBGs of the TB; in case of identifying that the DCI is associated with a retransmission of the TB based on the NDI, identifying one or more CBGs corresponding to a bit value of 1 included in the CBG indicator, the bit value 1 indicating corresponding CBG of the TB is present in the downlink data transmission; and decoding the identified CBGs.

PRIORITY

This application is a Continuation of U.S. application Ser. No.16/721,309, which was filed in the U.S. Patent and Trademark Office(USPTO) on Dec. 19, 2019, which is a Continuation of U.S. applicationSer. No. 16/676,050, which was filed in the USPTO on Nov. 6, 2019,issued as U.S. Pat. No. 10,693,599 on Jun. 23, 2020, which is aContinuation of U.S. application Ser. No. 16/416,843, which was filed inthe USPTO on May 20, 2019 issued as U.S. Pat. No. 10,615,922 on Apr. 7,2020, which is a Continuation of U.S. application Ser. No. 15/821,358,which was filed in the USPTO on Nov. 22, 2017, issued as U.S. Pat. No.10,298,362 on May 21, 2019, and claims priority under 35 U.S.C. § 119(a)to Korean Patent Application Serial No. 10-2016-0157171, which was filedin the Korean Intellectual Property Office on Nov. 24, 2016, and KoreanPatent Application Serial No. 10-2016-0177820, which was filed in theKorean Intellectual Property Office on Dec. 23, 2016, the entire contentof each of which is incorporated herein by reference.

BACKGROUND 1. Field of the Disclosure

The present disclosure relates generally to a wireless communicationsystem, and more particularly, to a method and an apparatus forperforming retransmission with respect to a code block requiring theretransmission among transport blocks, if retransmission of theinitially transmitted transport blocks is required.

2. Description of the Related Art

In order to meet the demand for wireless data traffic that is on anincreasing trend after commercialization of 4G communication systems,efforts have been made to develop improved 5G or pre-5G communicationsystem. For this reason, the 5G or pre-5G communication system is alsocalled a beyond 4G network communication system or a post LTE system.

In order to achieve high data rate, implementation of a 5G communicationsystem in an ultrahigh frequency (mmWave) band (e.g., like 60 GHz band)has been considered. In order to mitigate a path loss of radio waves andto increase a transfer distance of the radio waves in the ultrahighfrequency band, technologies of beamforming, massive MIMO, fulldimension MIMO (FD-MIMO), array antenna, analog beam-forming, and largescale antennas for the 5G communication system have been discussed.

Further, for system network improvement in the 5G communication system,technology developments have been made for an evolved small cell,advanced small cell, cloud radio access network (cloud RAN), ultra-densenetwork, device to device communication (D2D), wireless backhaul, movingnetwork, cooperative communication, coordinated multi-points (CoMP), andreception interference cancellation.

In addition, in the 5G system, hybrid FSK and QAM modulation (FQAM) andsliding window superposition coding (SWSC), which correspond to advancedcoding modulation (ACM) systems, and filter bank multicarrier (FBMC),non-orthogonal multiple access (NOMA), and sparse code multiple access(SCMA), which correspond to advanced connection technologies, have beendeveloped.

On the other hand, the Internet, which is a human centered connectivitynetwork where humans generate and consume information, is now evolvingto the Internet of things (IoT) where distributed entities, such asthings, exchange and process information. The Internet of everything(IoE), which is a combination of the IoT technology and big dataprocessing technology through connection with a cloud server, hasemerged.

As technology elements, such as sensing technology, wired/wirelesscommunication and network infrastructure, service interface technology,and security technology, have been demanded for IoT implementation, asensor network for machine-to-machine connection, machine-to-machine(M2M) communication, machine type communication (MTC), and so forth havebeen recently researched. Such an IoT environment may provideintelligent Internet technology (IT) services that create a new value tohuman life by collecting and analyzing data generated among connectedthings. The IoT may be applied to a variety of fields including smarthome, smart building, smart city, smart car or connected cars, smartgrid, health care, smart appliances and advanced medical servicesthrough convergence and combination between the existing informationtechnology (IT) and various industries.

Accordingly, various attempts have been made to apply the 5Gcommunication system to IoT networks. For example, technologies ofsensor network, machine to machine (M2M) communication, and MTC havebeen implemented by techniques for beam-forming, MIMO, and arrayantennas, which correspond to the 5G communication technology. As thebig data processing technology as described above, application of acloud radio access network (RAN) would be an example of convergencebetween the 5G technology and the IoT technology.

In a conventional wireless communication system, and particularly, in aconventional long term evolution (LTE) system, data is transmitted in aunit of a transport block (TB). The TB is normally divided into severalcode blocks (CBs), and channel coding is performed in a unit of a CB.However, after a decoding failure of an initial transmission,retransmission is performed in the unit of a TB, even if decoding ofonly one CB has failed. That is, conventionally, it is necessary that anentire TB be retransmitted.

SUMMARY

Accordingly, the present disclosure is made to address at least theproblems and/or disadvantages described above and to provide at leastthe advantages described below.

An aspect of the present disclosure is to provide a method forperforming retransmission in the unit of a CB.

Another aspect of the present disclosure is to provide a method ofperforming retransmission in a unit of a CB, in which a CB index fornotifying of an order of CBs is inserted into a CB to be operated.

Another aspect of the present disclosure is to provide a method and anapparatus capable of efficiently performing communication between a basestation and a terminal (or terminal-to-terminal communication), whereina terminal variously configures downlink or uplink frequency bandwidthsamong radio frequency resource regions used to perform downlink oruplink communication with a base station or a network, and receives adownlink signal or transmits an uplink signal through differentfrequency bandwidths in accordance with time or base stationconfiguration or the kind of signals received or transmitted by theterminal.

Another aspect of the present disclosure is to provide a method forperforming retransmission in a unit of a CB or a CB group if suchretransmission is necessary in transmitting one or two TBs, such that abase station and a terminal can perform efficient transmission to reduceunnecessary data transmission. That is, resources required for theretransmission can be saved through transmission of only a part of theinitial transmission during the retransmission using partialretransmission.

Another aspect of the present disclosure is to efficiently performcommunication between a base station and a terminal (orterminal-to-terminal communication), by configuring one or morefrequency bandwidths or radio resource regions so that they havedifferent sizes.

In accordance with an aspect of the present disclosure, a method isprovided for a terminal in a communication system. The method includesreceiving, from a base station, information on a number of code blockgroups (CBGs) of a transport block (TB) via higher layer signaling;identifying the number of the CBGs of the TB based on the information onthe number of the CBGs; receiving, from the base station, downlinkcontrol information (DCI) scheduling downlink data transmission, whereinthe DCI includes a new data indicator (NDI) and a CBG indicator;receiving, from the base station, downlink data corresponding to the TB;in case of identifying that the DCI is associated with an initialtransmission of the TB based on the NDI, identifying the CBGs of the TB;in case of identifying that the DCI is associated with a retransmissionof the TB based on the NDI, identifying one or more CBGs correspondingto a bit value of 1 included in the CBG indicator, the bit value 1indicating corresponding CBG of the TB is present in the downlink datatransmission; and decoding the identified CBGs.

In accordance with another aspect of the present disclosure, a method isprovided for a base station in a communication system. The methodincludes transmitting, to a terminal, information on a number of codeblock groups (CBGs) of a transport block (TB) via higher layersignaling; transmitting, to the terminal, downlink control information(DCI) scheduling downlink data transmission, wherein the DCI includes anew data indicator (NDI) and a CBG indicator; and transmitting, from thebase station, downlink data corresponding to the TB. In case that theNDI corresponds to an initial transmission of the TB, the downlink dataincludes the CBGs of the TB. In case that the NDI corresponds to aretransmission of the TB, the downlink data includes one or more CBGscorresponding a bit value of 1 included in the CBG indicator, the bitvalue 1 indicating a corresponding CBG of the TB is present in thedownlink data transmission.

In accordance with another aspect of the present disclosure, a terminalis provided for a wireless communication system. The terminal includes atransceiver; and a controller coupled with the transceiver andconfigured to receive, from a base station via the transceiver,information on a number of code block groups (CBGs) of a transport block(TB) via higher layer signaling, identify the number of the CBGs of theTB based on the information on the number of the CBGs, receive, from thebase station, via the transceiver, downlink control information (DCI)scheduling downlink data transmission, wherein the DCI includes a newdata indicator (NDI) and a CBG indicator, receive, from the basestation, via the transceiver, downlink data corresponding to the TB, incase of identifying that the DCI is associated with an initialtransmission of the TB based on the NDI, identify the CBGs of the TB, incase of identifying that the DCI is associated with a retransmission ofthe TB based on the NDI, identify one or more CBGs corresponding to abit value of 1 included in the CBG indicator, and the bit value 1indicates a corresponding CBG of the TB is present in the downlink datatransmission, and decode the identified CBGs.

In accordance with another aspect of the present disclosure, a basestation is provided for a wireless communication system. The basestation includes a transceiver; and a controller coupled with thetransceiver and configured to transmit, to a terminal, via thetransceiver, information on a number of code block groups (CBGs) of atransport block (TB) via higher layer signaling, transmit, to theterminal, via the transceiver, downlink control information (DCI)scheduling downlink data transmission, wherein the DCI includes a newdata indicator (NDI) and a CBG indicator, and transmit, from the basestation, via the transceiver, downlink data corresponding to the TB. Incase that the NDI corresponds to an initial transmission of the TB, thedownlink data includes the CBGs of the TB. In case that the NDIcorresponds to a retransmission of the TB, the downlink data includesone or more CBGs corresponding a bit value of 1 included in the CBGindicator, and the bit value 1 indicates a corresponding CBG of the TBis present in the downlink data transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present disclosure will be more apparent from thefollowing detailed description taken in conjunction with theaccompanying drawings, in which:

FIG. 1A illustrates a downlink time-frequency domain transmissionstructure of an LTE or LTE-advanced (LTE-A) system;

FIG. 1B illustrates an uplink time-frequency domain transmissionstructure of an LTE or LTE-A system;

FIG. 1C illustrates data for enhanced mobile broadband (eMBB),ultra-reliable and low-latency communications (URLLC), and massivemachine type communications (mMTC) allocated in frequency-time resourcesin a communication system;

FIG. 1D illustrates data for eMBB, URLLC, and mMTC allocated infrequency-time resources in a communication system;

FIG. 1E illustrates one transport block that is divided into severalcode blocks and includes a cyclic redundancy check (CRC) is addedthereto according to an embodiment of the present disclosure;

FIG. 1F illustrates a transmission method using an outer code accordingto an embodiment of the present disclosure;

FIG. 1G illustrates a communication system in which an outer code isused according to an embodiment of the present disclosure;

FIG. 1H illustrates an example of partial retransmission according to anembodiment of the present disclosure;

FIG. 1I illustrates an example bit configuration of a CB group indicatoraccording to an embodiment of the present disclosure;

FIG. 1J illustrates an example bit configuration of a CB group new dataindicator (NDI) according to an embodiment of the present disclosure;

FIG. 1KA is a flowchart illustrating a method for a base station toconfigure a bit field of a CB group indicator according to an embodimentof the present disclosure;

FIG. 1KB is a flowchart illustrating a method for a terminal to decodereceived data in accordance with a bit field of a CB group indicatoraccording to an embodiment of the present disclosure;

FIG. 1KC is a flowchart illustrating a method for a base station toconfigure a bit field of a CB group NDI according to an embodiment ofthe present disclosure;

FIG. 1KD is a flowchart illustrating a method for a terminal to decodereceived data in accordance with a bit field of a CB group NDI accordingto an embodiment of the present disclosure;

FIG. 1KE is a flowchart illustrating a method for a base station and aterminal according to an embodiment of the present disclosure;

FIG. 1L illustrates control information mapped for transmissionaccording to (an embodiment of the present disclosure;

FIG. 1MA is a flowchart illustrating a method for a base station toapply a channel code based on a control information type according to anembodiment of the present disclosure;

FIG. 1MB is a flowchart illustrating a method for a terminal to performchannel code decoding based on a control information type according toan embodiment of the present disclosure;

FIG. 1N illustrates a terminal according to an embodiment of the presentdisclosure;

FIG. 1O illustrates a base station according to an embodiment of thepresent disclosure;

FIG. 2A is a diagram illustrating a basic structure of a time-frequencydomain that is a radio resource region in which data or a controlchannel is transmitted in a downlink in an LTE system or a similarsystem;

FIG. 2B illustrates services being considered in 5G being multiplexedthrough one system for transmission;

FIGS. 2C and 2D illustrate communication systems to which the presentdisclosure is applied;

FIG. 2E illustrates a situation to be addressed according to anembodiment the present disclosure; and

FIGS. 2F and 2G illustrate methods proposed according to embodiments thepresent disclosure.

DETAILED DESCRIPTION First Embodiment

In order to meet the demand for wireless data traffic that is on anincreasing trend after commercialization of 4G communication systems,efforts have been made to develop improved 5G or pre-5G communicationsystem. For this reason, the 5G or pre-5G communication system is alsocalled a beyond 4G network communication system or a post LTE system. Inorder to achieve high data rate, implementation of a 5G communicationsystem in an ultrahigh frequency (mmWave) band (e.g., like 60 GHz band)has been considered.

In order to mitigate a path loss of radio waves and to increase atransfer distance of the radio waves in the ultrahigh frequency band,technologies of beamforming using array antennas, massive MIMO, fulldimension MIMO (FD-MIMO), hybrid beamforming, and large scale antennasfor the 5G communication system have been discussed. Further, for systemnetwork improvement in the 5G communication system, technologydevelopments have been made for an evolved small cell, advanced smallcell, cloud radio access network (cloud RAN), ultra-dense network,device to device communication (D2D), wireless backhaul, moving network,cooperative communication, coordinated multi-points (CoMP), andreception interference cancellation.

In addition, in the 5G system, hybrid FSK and QAM modulation (FQAM) andsliding window superposition coding (SWSC), which correspond to advancedcoding modulation (ACM) systems, and filter bank multicarrier (FBMC),non-orthogonal multiple access (NOMA), and sparse code multiple access(SCMA), which correspond to advanced connection technologies, have beendeveloped.

On the other hand, the Internet, which is a human centered connectivitynetwork where humans generate and consume information, is now evolvingto the Internet of things (IoT) where distributed entities, such asthings, exchange and process information. The Internet of everything(IoE), which is a combination of the IoT technology and big dataprocessing technology through connection with a cloud server, hasemerged. As technology elements, such as sensing technology,wired/wireless communication and network infrastructure, serviceinterface technology, and security technology, have been demanded forIoT implementation, a sensor network for machine-to-machine connection,machine-to-machine (M2M) communication, machine type communication(MTC), and so forth have been recently researched.

Such an IoT environment may provide intelligent Internet technology (IT)services that create a new value to human life by collecting andanalyzing data generated among connected things. The IoT may be appliedto a variety of fields including smart home, smart building, smart city,smart car or connected cars, smart grid, health care, smart appliancesand advanced medical services through convergence and combinationbetween the existing information technology (IT) and various industries.

Accordingly, various attempts have been made to apply the 5Gcommunication system to IoT networks. For example, technologies ofsensor network, machine to machine (M2M) communication, and MTC havebeen implemented by techniques for beam-forming, MIMO, and arrayantennas, which correspond to the 5G communication technology. As thebig data processing technology as described above, application of acloud radio access network (RAN) would be an example of convergencebetween the 5G technology and the IoT technology.

On the other hand, in a new radio access technology (NR) that is a new5G communication, various services are designed to be freely multiplexedin time and frequency resources, and accordingly, waveform/numerologyand a reference signal may be dynamically or freely allocated inaccordance with necessity of the corresponding services. In order toprovide optimum services to a terminal in wireless communication, it isimportant to provide optimized data transmission through measurement ofa channel quality and an interference amount, and thus accurate channelstate measurement is essential.

However, in the case of 5G channels, in contrast with 4G communicationsin which channel and interference characteristics are not greatlychanged in accordance with frequency resources, the channel andinterference characteristics are greatly changed in accordance withservices, and thus support of frequency resource group (FRG)-levelsubset for divided measurement of the services becomes necessary. On theother hand, in an NR system, the kind of supported services may bedivided into categories of enhanced mobile broadband (eMBB), massivemachine type communications (mMTC), and ultra-reliable and low-latencycommunications (URLLC). The eMBB may be a service aiming at high-speedtransmission of high-capacity data, and the mMTC may be a service aimingat minimization of a terminal power and connection of multipleterminals. The URLLC may be a service aiming at ultra-reliability andlow latency. Different requirements may be applied in accordance withthe kind of services applied to the terminal.

In a communication system as described above, a plurality of servicesmay be provided to a user, and in order to provide such services to theuser, there is a need for a method capable of providing respectiveservices to match the features in the same time domain and an apparatususing the same.

Hereinafter, various embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings.However, the present disclosure is not limited to the embodimentsdisclosed hereinafter, but can be implemented in diverse forms.

The matters defined in the description, such as the detailedconstruction and elements, are provided to assist those of ordinaryskill in the art in a comprehensive understanding of the disclosure, andthe present disclosure is only defined within the scope of the appendedclaims.

In explaining the embodiments, explanations of technical contents whichare well known in the art to which the present disclosure pertains andare not directly related to the present disclosure will be omitted, inorder to clearly describe the present disclosure more without obscuringthe same with unnecessary detail.

In the accompanying drawings, sizes and relative sizes of someconstituent elements may be exaggerated, omitted, or brieflyillustrated. Further, sizes of the respective constituent elements donot completely reflect the actual sizes thereof. Additionally, the samedrawing reference numerals may be used for the same or correspondingelements across various figures.

The aspects and features of the present disclosure and methods forachieving the aspects and features will be apparent by referring to theembodiments to be described in detail with reference to the accompanyingdrawings. However, the present disclosure is not limited to theembodiments disclosed hereinafter, but can be implemented in diverseforms. The matters defined in the description, such as the detailedconstruction and elements, are nothing but specific details provided toassist those of ordinary skill in the art in a comprehensiveunderstanding of the disclosure, and the present disclosure is onlydefined within the scope of the appended claims. In the entiredescription of the present disclosure, the same drawing referencenumerals are used for the same elements across various figures.

Each block of a flowchart, and combinations of blocks in a flowchart,can be implemented by computer program instructions. These computerprogram instructions can be provided to a processor of a general purposecomputer, special purpose computer, or other programmable dataprocessing apparatus to produce a machine, such that the instructions,which execute via the processor of the computer or other programmabledata processing apparatus, instruct a device to implement the functionsspecified in the flowchart block or blocks. These computer programinstructions may also be stored in a computer usable orcomputer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer usable orcomputer-readable memory produce an article of manufacture includinginstruction means that implement the function specified in the flowchartblock or blocks. The computer program instructions may also be loadedonto a computer or other programmable data processing apparatus to causea series of operational steps to be performed on the computer or otherprogrammable apparatus to produce a computer implemented process suchthat the instructions that execute on the computer or other programmableapparatus provide steps for implementing the functions specified in theflowchart block or blocks.

Each block of a flowchart may represent a module, segment, or portion ofcode, which includes one or more executable instructions forimplementing the specified logical function(s). Alternatively, thefunctions noted in the blocks may occur in different orders. Forexample, two blocks shown in succession may in fact be executedsubstantially concurrently or the blocks may sometimes be executed inthe reverse order, depending upon the functionality involved.

Herein, the term “unit”, may refer to a software and/or hardwarecomponent, such as a field-programmable gate array (FPGA) or anapplication-specific integrated circuit (ASIC), which performs certaintasks. However, a “unit” is not limited to software or hardware. Theterm “unit” may advantageously be configured to reside on theaddressable storage medium and configured to execute on one or moreprocessors. Thus, a “unit” may include, by way of example, components,such as software components, object-oriented software components, classcomponents and task components, processes, functions, attributes,procedures, subroutines, segments of program code, drivers, firmware,microcode, circuitry, data, databases, data structures, tables, arrays,and variables. The functionality provided for in the components and“units” may be combined into fewer components and “units” or furtherseparated into additional components and “units”. Further, thecomponents and “units” may be implemented to operate one or more centralprocessing units (CPUs) in a device or a security multimedia card. A,“unit” may include one or more processors.

A wireless communication system has escaped from an initialvoice-oriented service providing system, and has been developed as abroadband wireless communication system that provides high-speed andhigh-quality packet data services in accordance with the communicationstandards, such as high speed packet access (HSPA) of 3GPP, long termevolution (LTE) or evolved universal terrestrial radio access (E-UTRA),LTE-advanced (LTE-A), high rate packet data (HRPD) of 3GPP2,ultra-mobile broadband (UMB), and 802.16e of IEEE. Further, for the 5Gwireless communication system, 5G or new radio (NR) communicationstandards have been made.

In an LTE system that is a representative example of the broadbandwireless communication system, an orthogonal frequency divisionmultiplexing (OFDM) method is adapted for a downlink (DL), and a singlecarrier frequency division multiple access (SC-FDMA) method is adaptedfor an uplink (UL). The uplink means a radio link through which aterminal (user equipment (UE) or mobile station (MS)) transmits data ora control signal to a base station (BS or eNode B), and the downlinkmeans a radio link through which the base station transmits data or acontrol signal to the terminal. In general, the multiple access methodas described above separates data and control information from eachother for each user by allocating and operating time-frequency resourceson which the data or the control information is carried for each user sothat the resources do not overlap each other, that is, so that theorthogonality is realized.

The LTE system adapts a hybrid automatic repeat request (HARQ) method inwhich a physical layer re-transmits the corresponding data if a decodingfailure occurs during initial transmission. The HARQ method enables areceiver to transmit information (negative acknowledgement (NACK)) fornotifying a transmitter of the decoding failure if the receiver couldnot accurately decode the data, so that the transmitter can re-transmitthe corresponding data on the physical layer. The receiver combines thedata re-transmitted by the transmitter with the previous data of whichthe decoding has failed to heighten data reception performance. Further,if the receiver has accurately decoded the data, it transmitsinformation (acknowledgement (ACK)) for notifying the transmitter of adecoding success, so that the transmitter can transmit new data.

FIG. 1A illustrates a time-frequency domain that is a radio resourceregion from which data or a control channel is transmitted through adownlink in an LTE system.

Referring to FIG. 1A, a horizontal axis represents a time domain, and avertical axis represents a frequency domain. In the time domain, theminimum transmission unit is an orthogonal frequency divisionmultiplexing (OFDM) symbol, and N_(symb) OFDM symbols 1 a-02 areincluded in one slot 1 a-06, and two slots constitute one subframe 1a-05. The length of a slot is 0.5 ms, and the length of a subframe is0.1 ms. Further, the radio frame 1 a-14 is a time domain intervalincluding 10 subframes. The minimum transmission unit in the frequencydomain is a subcarrier, and the transmission bandwidth of the entiresystem is N_(BW) subcarriers 1 a-04 in total.

In the time-frequency domain, the basic unit is a resource element (RE)1 a-12, which may be indicated as an OFDM symbol index and a subcarrierindex.

A resource block (RB) 1 a-08 or a physical resource block (PRB) isdefined as N_(symb) successive OFDM symbols 1 a-02 in the time domainand N_(RB) successive subcarriers 1 a-10 in the frequency domain.Accordingly, the RB 1 a-08 is composed of N_(symb)×N_(RB) REs 1 a-12.

In general, the minimum transmission unit of data is the RB unit asdescribed above. In an LTE system, it is common that N_(symb)=7,N_(RB)=12, and N_(BW) and N_(RB) are in proportion to the systemtransmission bandwidth. However, in another system that is not an LTEsystem, different values may be used.

The data rate increases in proportion to the number of RBs beingscheduled to a terminal. In an LTE system, 6 transmission bandwidths aredefined and operated. In a frequency division duplex (FDD) system thatdivides and operates a downlink and an uplink through a frequency, thetransmission bandwidth of the downlink and the transmission bandwidth ofthe uplink may differ from each other. The channel bandwidth indicates aradio frequency (RF) bandwidth that corresponds to the systemtransmission bandwidth.

Table 1, below, presents a corresponding relationship between a systemtransmission bandwidth defined in an LTE system and a channel bandwidth.For example, in an LTE system having a channel bandwidth of 10 MHz, atransmission bandwidth includes 50 RBs.

TABLE 1 Channel bandwidth BW_(Channel) [MHz] 1.4 3 5 10 15 20Transmission 6 15 25 50 75 100 bandwidth configuration N_(RB)

Downlink control information may be transmitted within the first N OFDMsymbols in the subframe, e.g., N={1, 2, 3}. Accordingly, based on theamount of control information to be transmitted in the current subframe,the value N may be variably applied for each subframe. The transmittedcontrol information includes a control channel transmission intervalindicator indicating how many OFDM symbols the control information istransmitted through, scheduling information on downlink data or uplinkdata, and a hybrid automatic repeat request (HARQ)acknowledgement/negative acknowledgement (ACK/NACK) signal.

In an LTE system, scheduling information on the downlink data or theuplink data is transferred from the base station to the terminal throughdownlink control information (DCI). The DCI may be defined in accordancewith various formats, and may indicate whether the schedulinginformation is uplink (UL) data scheduling information (a UL grant) ordownlink (DL) data scheduling information (a DL grant), whether the DCIis compact DCI having a small size of control information, whetherspatial multiplexing using multiple antennas is applied, or whether theDCI is DCI for power control. For example, a DCI format 1 for schedulingcontrol information (a DL grant) of the downlink data may include atleast one of the following control information.

-   -   Resource allocation type 0/1 flag: This flag notifies whether a        resource allocation type is type 0 or type 1. The type 0        allocates resources in a unit of a resource block group (RBG) by        applying a bitmap type. In an LTE system, the basic unit for        scheduling is an RB that is expressed as a time and frequency        domain resource, and an RBG includes a plurality of RBs to be        considered as the basic unit for scheduling in the type 0. The        type 1 allocates a specific RB in the RBG.    -   Resource block assignment: This assignment indicates an RB that        is allocated for data transmission. The expressed resource is        determined in accordance with the system bandwidth and the        resource allocation method.    -   Modulation and coding scheme (MCS): This scheme indicates a        modulation method used for data transmission and the size of a        transport block that is data to be transmitted.    -   HARQ process number: This number indicates the process number of        HARQ.    -   New data indicator: This indicator indicates whether HARQ        transmission is an initial transmission or a retransmission.    -   Redundancy version: This version indicates a redundancy version        of HARQ.    -   Transmit power control (TPC) command for physical uplink control        channel (PUCCH): This command indicates a transmission power        control command for a PUCCH that is an uplink control channel.

The DCI may be transmitted through a physical downlink control channel(PDCCH) (or control information) that is a downlink physical controlchannel or an enhanced PDCCH (EPDCCH) (or enhanced control information)after passing through a channel coding and modulation process.

In general, the DCI is scrambled by a specific radio network temporaryidentifier (RNTI) (or terminal identifier) independently with respect toeach terminal, is added with a CRC, is channel-coded, and then isconfigured as an independent PDCCH to be transmitted. In the timedomain, the PDCCH is mapped and transmitted for the control channeltransmission interval. The mapping location of the frequency domain ofthe PDCCH is determined by the identifier (ID) of each terminal, and thePDCCH is transmitted through the transmission band of the whole system.

The downlink data may be transmitted on a physical downlink sharedchannel (PDSCH). The PDSCH may be transmitted after the control channeltransmission interval, and scheduling information, such as a concretemapping location or a modulation method in the frequency domain, isdetermined based on the DCI that is transmitted through the PDCCH.

Through an MCS among control information constituting the DCI, the basestation notifies the terminal of the modulation scheme applied to thePDSCH to be transmitted to the terminal and a transport block size(TBS). For example, the MCS may include 5 bits, more than 5 bits, orless than 5 bits. The TBS corresponds to a size of a TB before channelcoding for error correction is applied thereto, in order to betransmitted by the base station.

A TB may include a medium access control (MAC) header, a MAC controlelement (CE), one or more MAC service data units (SDUs), and paddingbits. Further, the TB may indicate a unit of data downloaded from a MAClayer to a physical layer, or a MAC protocol data unit (PDU).

Modulation methods supported in an LTE system are quadrature phase shiftkeying (QPSK), 16 quadrature amplitude modulation (16QAM), and 64QAM,and respective modulation orders (Qm) correspond to 2, 4, and 6. Thatis, for QPSK modulation, 2 bits per symbol may be transmitted, for 16QAMmodulation, 4 bits per symbol may be transmitted, and for 64QAMmodulation, 6 bits per symbol may be transmitted. Further, in accordancewith the system modification, a modulation method of 256QAM or more maybe used.

FIG. 1B illustrates a time-frequency domain that is a radio resourceregion from which data or a control channel is transmitted through anuplink in an LTE-A system.

Referring to FIG. 1B, a horizontal axis represents a time domain, and avertical axis represents a frequency domain. In the time domain, theminimum transmission unit is a single carrier frequency divisionmultiple access (SC-FDMA) symbol 1 b-02, and N_(symb) ^(UL) SC-FDMAsymbols constitute one slot 1 b-06. Further, two slots constitute onesubframe 1 b-05. The minimum transmission unit in the frequency domainis a subcarrier, and the transmission bandwidth 1 b-04 of the entiresystem is N_(BW) subcarriers in total. N_(BW) may have a value that isin proportion to the system transmission band.

In the time-frequency domain, the basic unit of a resource is a resourceelement (RE) 1 b-12, and the resource may be defined as an SC-FDMAsymbol index and a subcarrier index. The RB pair 1 b-08 is defined asN_(symb) ^(UL) successive SC-FDMA symbols in the time domain and N_(sc)^(RB) successive subcarriers in the frequency domain. Accordingly, oneRB includes N_(symb) ^(UL)×N_(sc) ^(RB) REs.

In general, the minimum transmission unit of data or control informationis the RB unit. A PUCCH is mapped onto the frequency domaincorresponding to 1 RB, and is transmitted for one subframe.

In an LTE system, the timing relationship between a PDSCH that is aphysical channel for transmitting downlink data or a PDCCH/EPDDCHincluding a semi-persistent scheduling (SPS) release and a PUCCH or aPUSCH that is an uplink physical channel through which a correspondingHARQ ACK/NACK is transmitted has been defined. For example, in an LTEsystem that operates as an FDD, the HARQ ACK/NACK corresponding to thePDSCH transmitted in the (n−4)-th subframe or the PDCCH/EPDCCH includingthe SPS release is transmitted through the PUCCH or the PUSCH in then-th subframe.

In an LTE system, a downlink HARQ uses an asynchronous HARQ method inwhich data re-transmission time is not fixed. That is, if the HARQ NACKis fed back from the terminal with respect to the initially transmitteddata transmitted by the base station, the base station freely determinesthe transmission time of re-transmitted data through the schedulingoperation. The terminal buffers the data that is determined as an error,as the result of decoding the received data for the HARQ operation, andthen performs combining with the next re-transmitted data.

If the PDSCH including the downlink data transmitted from the basestation in the subframe n is received, the terminal transmits the uplinkcontrol information including the HARQ ACK or NACK of the downlink datato the base station through the PUCCH or PUSCH in the subframe n+k.Here, k is differently defined in accordance with the FDD or timedivision duplex (TDD) of the LTE system and the subframe configuration.For example, in an FDD LTE system, k is fixed to 4. However, in a TDDLTE system, k may be changed in accordance with the subframeconfiguration and the subframe number.

In an LTE system, in contrast with a downlink HARQ, an uplink HARQadapts a synchronous HARQ method in which the data transmission time isfixed. That is, the uplink/downlink timing relationship among a physicaluplink shared channel (PUSCH) that is a physical channel fortransmitting the uplink data, a PDCCH that is a preceding downlinkcontrol channel, and a physical hybrid indicator channel (PHICH) that isa physical channel through which the downlink HARQ ACK/NACKcorresponding to the PUSCH is transmitted is fixed based on thefollowing:

-   -   If the PDCCH including the uplink scheduling control information        transmitted from the base station in the subframe n or the PHICH        through which the downlink HARQ ACK/NACK is transmitted is        received, the terminal transmits the uplink data corresponding        to the control information through the PUSCH in the subframe        n+k. Here, k is differently defined in accordance with the FDD        or TDD of the LTE system and its configuration. For example, in        an FDD LTE system, k is fixed to 4.    -   In a TDD LTE system, k may be changed in accordance with the        subframe configuration and the subframe number. In the FDD LTE        system, if the base station transmits, to the terminal, an        uplink scheduling grant or a downlink control signal and data in        the subframe n, the terminal receives the uplink scheduling        grant or the downlink control signal and the data in the        subframe n. When receiving the uplink scheduling grant in the        subframe n, the terminal transmits uplink data in the subframe        n+4. When receiving the downlink control signal and the data in        the subframe n, the terminal transmits the HARQ ACK or NACK for        the downlink data in the subframe n+4. Accordingly, the time at        which the terminal receives the uplink scheduling grant and        transmits the uplink data or the terminal receives the downlink        data and transfers the HARQ ACK or NACK, becomes 3 ms        corresponding to three subframes.    -   Further, if the terminal receives a PHICH that carries the        downlink HARQ ACK/NACK from the base station in the subframe i,        the PHICH corresponds to the PUSCH transmitted by the terminal        in the subframe i-k. Here, k is differently defined in        accordance with the FDD or TDD of the LTE system and its        configuration. For example, in an FDD LTE system, k is fixed        to 4. However, in a TDD LTE system, k may be changed in        accordance with the subframe configuration and the subframe        number.

FIGS. 1C and 1D illustrate data for eMBB, URLLC, and mMTC allocated infrequency-time resources in a communication system.

Referring to FIGS. 1C and 1D, a method for allocating frequency and timeresources for information transmission in each system will be described.

Referring to FIG. 1C, data for eMBB, URLLC, and mMTC is allocated in theentire system frequency band 1 c-00. If URLLC data 1 c-03, 1 c-05, and 1c-07 are generated and transmission thereof becomes necessary while eMBB1 c-01 and mMTC 1 c-09 are allocated in a specific frequency band to betransmitted, the URLLC data 1 c-03, 1 c-05, and 1 c-07 may betransmitted by emptying portions that have already been allocated withthe eMBB 1 c-01 and mMTC 1 c-09 or without transmitting the eMBB 1 c-01and mMTC 1 c-09.

Among the above-described services, since the URLLC is required toreduce latency, the URLLC data 1 c-03, 1 c-05, and 1 c-07 may betransmitted where they are allocated to a part of the resource to whichthe eMBB 1 c-01 has been allocated. If the URLLC is transmitted where itis additionally allocated to the resource to which the eMBB has beenallocated, the eMBB data may not be transmitted, and thus, thetransmission performance of the eMBB data may be lowered. That is, inthe above-described example, the eMBB data transmission may fail due tothe URLLC allocation.

Referring to FIG. 1D, the entire system frequency band 1 d-00 is dividedinto subbands 1 d-02, 1 d-04, and 1 d-06, which are used to transmitservices and data. Information related to the subband configuration maybe predetermined, and this information may be transmitted from a basestation to a terminal through upper layer signaling. Further,information related to the subbands 1 d-02, 1 d-04, and 1 d-06 may beoptionally divided by the base station or a network node, and servicesmay be provided to the terminal without transmitting separate subbandconfiguration information to the terminal. As illustrated in FIG. 1D,subband 1 d-02 is used to transmit eMBB data, subband 404 is used totransmit URLLC data, and subband 1 d-06 is used to transmit mMTC data.

The length of a transmission time interval (TTI) used to transmit URLLCmay be shorter than the length of a TTI used to transmit eMBB or mMTC.Further, a response to the URLLC related information can be transmittedfaster than the eMBB or mMTC, and thus, the information can betransmitted or received at low latency.

FIG. 1E illustrates a transport block being divided into several codeblocks and including a CRC according to an embodiment.

Referring to FIG. 1E, in an uplink or a downlink, a CRC 1 e-03 may beadded to a last portion or a head portion of the TB 1 e-01. The CRC 1e-03 may include 16 or 24 bits or a prefixed number of bits, or mayinclude a variable number of bits in accordance with the channelsituations. The CRC 1 e-03 may be used to determine success/failure ofthe channel coding.

Blocks 1 e-01 and 1 e-03 to which a TB and a CRC are added may bedivided into several CBs 1 e-07, 1 e-09, 1 e-11, and 1 e-13 (1 e-05).The maximum size of a CB may be predetermined, and in this case, thelast code block 1 e-13 may have a size that is larger or smaller thanthat of other CBs, or may have a length that matches the length of otherCBs by putting 0, a random value, or 1 thereto.

CRCs 1 e-17, 1 e-19, 1 e-21, and 1 e-23 may be added to the divided codeblocks (1 e-15). The CRC may include 16 or 24 bits or a prefixed numberof bits, and may be used to determine success/failure of the channelcoding. However, the CRC 1 e-03 added to the TB and the CRCs 1 e-17, 1e-19, 1 e-21, and 1 e-23 added to the CBs may be omitted depending onthe kind of the channel code to be applied to the CB.

For example, if a low density parity check (LDPC) code, other than aturbo code, is applied to the CB, the CRCs 1 e-17, 1 e-19, 1 e-21, and 1e-23 to be inserted into the CB may be omitted. However, even if theLDPC is applied, the CRCs 1 e-17, 1 e-19, 1 e-21, and 1 e-23 may beadded to the CB as they are. Even if a polar code is used, the CRC maybe added or omitted.

FIG. 1F illustrates a transmission method in which an outer code isused, and FIG. 1G illustrates a communication system in which an outercode is used.

Referring to FIGS. 1F and 1G, a method for transmitting a signal usingan outer code will be described.

Referring to FIG. 1F, a transport block is divided into several codeblocks, and bits or symbols 1 f-04 that are at the same location in therespective code blocks may be encoded with the second channel code togenerate parity bits or symbols 1 f-06 (1 f-02). Thereafter, CRCs may beadded to the respective code blocks and parity code blocks generatedthrough the second channel code encoding (1 f-08 and 1 f-10).

The addition of the CRCs may differ depending on the kind of the channelcode. For example, if a turbo code is used as the first channel code,the CRCs 1 f-08 and 1 f-10 are added, but thereafter, the respectivecode blocks and parity code blocks may be encoded through the firstchannel code encoding. The transport block is transferred from an upperlayer to a physical layer.

In the physical layer, the TB is considered as data. The CRC is added tothe TB. In order to generate the CRC, TB data bits and a cyclicgenerator polynomial may be used, and the cyclic generator polynomialmay be defined in various methods.

For example, if the cyclic generator polynomial for 24-bit CRC isg_(CRC24A)(D)=D²⁴+D²³+D¹⁸+D¹⁷+D¹⁴+D¹¹+D¹⁰+D⁷+D⁶+D⁵+D⁴+D³+D+1, and L isL=24, the CRC p₀, p₁, p₂, p₃, . . . , p_(L-1) is determined as a valueobtained by dividing α₀D^(A+23)+α₁D^(A+22)+ . . .+α_(A−1)D²⁴+p₀D²³+p₁D²²+ . . . +p₂₂D¹+p₂₃ by the g_(CRC24A)(D) with theremainder of 0 with respect to TB data a₀, a₁, a₂, a₃, . . . , a_(A−1).

In the above-described example, although the CRC length L=24, variouslengths, such as, 12, 16, 32, 40, 48, and 64 may be used. The CRCs areadded to the divided CBs, and a cyclic generator polynomial that isdifferent from that of the CRC of the TB may be used as the CRC of theCB.

In a conventional LTE system, during retransmission due to an initialtransmission failure, the initially transmitted TB is retransmitted.However, retransmission in a unit of a CB or several CBs other than inthe unit of a TB may become possible. For this, a terminal may transmitseveral-bit HARQ-ACK feedback per TB. Further, during theretransmission, information is provided as control information forscheduling transmitted from the base station, indicating what portion ofthe TB is being retransmitted.

Referring to FIG. 1G, if an outer code is used, data to be transmittedpasses through a second channel coding encoder 1 g-09. As a channel codeused for the second channel coding, e.g., a Reed-Solomon code, a DCHcode, a raptor code, or a parity bit generation code may be used. Thebits or symbols that have passed through the second channel codingencoder 1 g-09 pass through the first channel coding encoder 1 g-11. Achannel code used for the first channel coding may be a convolutionalcode, an LDPC code, a turbo code, or a polar code.

If the channel coded symbols are received in a receiver, after passingthrough a channel 1 g-13, the receiver side may successively operate thefirst channel coding decoder 1 g-15 and the second channel codingdecoder 1 g-17 based on the received signal. The first channel codingdecoder 1 g-15 and the second channel coding decoder 1 g-17 may performoperations corresponding to the operations of the first channel codingencoder 1 g-11 and the second channel coding encoder 1 g-09.

However, if the outer code is not used, although the first channelcoding encoder 1 g-11 and the first channel coding decoder 1 g-05 areused in the transceiver, the second channel coding encoder and thesecond channel coding decoder are not used. Even if the outer code isnot used, the first channel coding encoder 1 g-11 and the first channelcoding decoder 1 g-05 may be configured in the same manner as when theouter code is used.

Herein, an eMBB service is referred to as a first type service, and datafor eMBB is referred to as first type data. The first type service orthe first type data is not limited to the eMBB, but may correspond to ascenario in which high-speed data transmission is required or broadbandtransmission is performed.

Further, an URLLC service is referred to as a second type service, anddata for URLLC is referred to as second type data. The second typeservice or the second type data is not limited to the URLLC, but maycorrespond to a scenario in which low latency is required orultra-reliable transmission is necessary, or may correspond to anothersystem in which both low-latency and ultra-reliability are required.

Further, an mMTC service is referred to as a third type service, anddata for mMTC is referred to as third type data. The third type serviceor the third type data is not limited to the mMTC, but may correspond toa scenario in which a low speed, a wide coverage, or a low power isrequired.

Further, the first type service may or may not include the third typeservice.

In order to transmit three kinds of services or data as described above,different physical layer channel structures may be used for therespective types. For example, at least one of a TTI length, a frequencyresource allocation unit, a control channel structure, and a datamapping method may differ.

Although three kinds of services and three kinds of data have beendescribed, more kinds of services and corresponding data may exist, andthe present disclosure may be applied thereto.

Although methods and the apparatuses are described below with referenceto an LTE or LTE-A system, and use terminology of these systems, thepresent disclosure is also applicable to other wireless communicationsystems. For example, 5G mobile communication technology (5G or newradio (NR)) developed after LTE-A may be included therein.

As described above, an embodiment of the present disclosure proposes amethod for defining transmission/reception operations of a terminal anda base station for transmitting first to third type services or data,and for operating terminals that receive different types of services ordata scheduling together in the same system. The first to third typeterminals receive the first to third type services or data scheduling.The first to third type terminals may be the same terminals or differentterminals.

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings. In describing thepresent disclosure, a detailed description of related functions orconfigurations will be omitted if it is determined that it obscures thedisclosure in unnecessary detail. Further, all terms used in thedescription are general terms that are widely used in consideration oftheir functions in the present disclosure, but may differ depending onintentions of a person skilled in the art to which the presentdisclosure belongs, customs, or appearance of new technology.Accordingly, they should be defined based on the contents of the wholedescription of the present disclosure.

Herein, a base station that performs resource allocation to the terminalmay be an eNode B, a Node B, a base station (BS), a radio access unit, abase station controller, or node on a network. The terminal may includea user equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, or a multimedia system that can perform acommunication function.

A DL is a radio transmission path of a signal that is transmitted fromthe base station to the terminal, and a UL is a radio transmission pathof a signal that is transmitted from the terminal to the base station.

Further, although an LTE or LTE-A system is hereinafter exemplified inexplaining an embodiment of the present disclosure, the embodiment ofthe present disclosure may be applied to even other communicationsystems having similar technical backgrounds or channel types. Forexample, the 5G mobile communication technology (5G or new radio (NR))developed after LTE-A may be included therein. Further, the embodimentof the present disclosure may also be applied to other communicationsystems through partial modifications thereof in a range that does notgreatly deviate from the scope of the present disclosure through thejudgment of those skilled in the art.

A TTI may be a unit in which a control signal and a data signal aretransmitted, or may be a unit in which the data signal is transmitted.For example, in a downlink in existing conventional LTE system, the TTIbecomes a subframe that is a time unit of 1 ms. However, in an uplinkaccording to an embodiment of the present disclosure, a TTI is a unit inwhich a control signal or a data signal is transmitted, or is a unit inwhich the data signal is transmitted. In the uplink in the conventionalLTE system, the TTI is a subframe that is a time unit of 1 ms in thesame manner as in the down link.

Unless specially mentioned, a shortened-TTI terminal includes a terminalcapable of transmitting control information, data, control information,and/or data at a TTI of 1 ms or shorter, and a normal-TTI type terminalincludes a terminal capable of transmitting control information, data,control information and/or data at the TTI of 1 ms. Further, in thepresent disclosure, a shortened-TTI, a shorter-TTI, a short TTI, and ansTTI have the same meaning, and may be used interchangeably. Further, inthe present disclosure, a normal-TTI, a subframe TTI, and a legacy TTIhave the same meaning, and may be used interchangeably.

As described above, 1 ms that is a basis for discriminating between theshortened-TTI and the normal-TTI may differ depending on the system.That is, in a specific NR system, based on 0.2 ms, if the TTI is shorterthan 0.2 ms, it may be a shortened-TTI, and if the TTI is 0.2 ms, it maybe a normal-TTI.

An important factor of performance of a wireless cellular communicationsystem is packet data latency. In an LTE system, signaltransmission/reception is performed in a unit of a subframe having a TTIof 1 ms. Therefore, a terminal having a TTI shorter than 1 ms (i.e., ashort-TTI UE) may be supported.

However, in the NR, which is a 5G mobile communication system, a TTI maybe shorter than 1 ms.

It is expected that a short-TTI terminal will be suitable for a voiceover LTE (VoLTE) service in which the latency is important and a remotecontrol service. Further, the short-TTI terminal is expected to becapable of realizing cellular-based mission-critical Internet of things(IoT).

In the present disclosure, shortened-TTI data refers to data that istransmitted from a PDSCH or PUSCH in a unit of a shortened TTI, and anormal-TTI data refers to data that is transmitted from the PDSCH orPUSCH in a unit of a subframe. A control signal for a shortened-TTIrefers to a control signal for a shortened-TTI mode operation, i.e., ansPDCCH, and a control signal for a normal-TTI refers to a control signalfor a normal-TTI mode operation. For example, a control signal for anormal-TTI may be a physical control format indicator channel (PCFICH),a PHICH, PDCCH, EPDCCH, or PUCCH in a conventional LTE system.

Herein, the terms “physical channel” and “signal” may be usedinterchangeably with “data” or “control signal”. For example, althoughthe PDSCH is a physical channel through which normal-TTI data istransmitted, the PDSCH may be referred to as normal-TTI data. Further,although the sPDSCH is a physical channel through which shortened-TTIdata is transmitted, the sPDSCH may be referred to as shortened-TTIdata. Similarly, shortened-TTI data transmitted in the downlink and theuplink may be referred to as sPDSCH and sPUSCH.

Herein, an uplink scheduling grant signal and a downlink data signal arereferred to as a first signal, and an uplink data signal for the uplinkscheduling grant and the HARQ ACK/NACK for the downlink data signal arereferred to as a second signal. A signal that expects a response fromthe terminal among signals that the base station transmits to theterminal may be the first signal, and the response signal of theterminal corresponding to the first signal may be the second signal.Further, the service kinds (or types) of the first signal and the secondsignal may belong to categories, such as eMBB, mMTC, and URLLC.

A TTI length of the first signal refers to a length of time over whichthe first signal is transmitted, and a TTI length of the second signalrefers to a length of time over which the second signal is transmitted.The transmission timing of the second signal may be information on whenthe terminal transmits the second signal and when the base stationreceives the second signal, and may be referred to as the second signaltransmission/reception timing.

Unless a TDD system is specifically mentioned, it is generally assumedthat the communication system being referred to is an FDD system.However, the methods and apparatuses according to the present disclosureare applicable to a TDD system through simple modification thereof.

Herein, an upper (or upper layer) signaling is a method for transferringa signal from the base station to the terminal using the downlink datachannel of the physical layer or a method for transferring a signal fromthe terminal to the base station using the uplink data channel of thephysical layer, and may also be referred to as a radio resource control(RRC) signaling or a MAC CE.

Hereinafter, ┌X┐ indicates a smallest integer that is larger than X, and└X┘ indicates a largest integer that is smaller than X.

FIG. 1H illustrates an example of partial retransmission according to anembodiment of the present disclosure.

Referring to FIG. 1H, a base station schedules eMBB data 1 h-03 to aterminal a using a control signal 1 h-01. Thereafter, if the eMBB data 1h-03 is transmitted, a part 1 h-07 of a resource onto which the eMBBdata is to be mapped is used to transmit another data 1 h-07 to theterminal a or another terminal b. Thereafter, a part 1 h-05 of the eMBBdata that has been transmitted or has not been transmitted to theterminal a is retransmitted to a next TTI 1 h-10. The unit of thepartial retransmission may be a CB or a CB group including one or moreCBs.

The eMBB control signal 1 h-01 transfers scheduling information for theeMBB data 1 h-03 to the terminal a. If URLLC data is generated duringtransmission of the eMBB data 1 h-03, the base station transmits a URLLCcontrol signal and data to terminal b (1 h-07). The transmission of theURLLC control signal and data is performed through mapping of the URLLCcontrol signal and the data (1 h-07) onto a resource to be transmitted,without mapping a part of the existing scheduled eMBB data 1 h-03 ontothe resource.

Accordingly, a part of the eMBB is not transmitted from the existing TTI1 h-05. As a result, the eMBB terminal may fail to decode the eMBB data.To supplement this, a part of the eMBB data that is not transmitted atthe TTI 1 h-05 is transmitted at the TTI 1 h-10 (1 h-13). The partialtransmission is performed at the TTI 1 h-10 after the initialtransmission, and may be performed without receiving HARQ-ACKinformation for the initial transmission from the terminal. Through thepartial transmission, scheduling information may be transferred from acontrol signal region 1 h-09 of the next TTI.

The control signal region 1 h-09 of the next TTI may include informationon a symbol location at which the resource mapping of the eMBB oranother data 1 h-17 starts when the eMBB or another data 1 h-17 istransmitted to another terminal (1 h-11). The information may betransferred from partial bits of the DCI transmitted from the controlsignal region 1 h-09. Using the information on the symbol location atwhich resource mapping of the eMBB or another data 1 h-17 starts, aspecific symbol performs partial transmission 1 h-15 for the previousinitial transmission. The eMBB control signal 1 h-01 or 1 h-09 of FIG.1H may not be transferred from the entire indicated region, but may betransferred only from the partial region. Further, it is also possibleto transfer the control signal 1 h-01 or 1 h-09 from a partial frequencyband other than the entire frequency band.

Although the partial retransmission 1 h-15 is performed at the next TTIsince a part of the eMBB is not transmitted for transmission of theURLLC data 1 h-07, the partial retransmission may be used in a mannerthat the base station optionally retransmits a specific part of dataalthough it is not caused by the URLLC data transmission. Further,because a part of the eMBB is not transmitted for transmission of theURLLC data 1 h-07, the partial retransmission 1 h-05 is performed at thenext TTI. However, the partial retransmission 1 h-15 may bediscriminated as the initial transmission of the corresponding part.That is, the terminal that has received the partial retransmission 1h-15 at the next TTI 1 h-10 does not perform HARQ decoding throughcombination with the received part at the previous TTI 1 h-05, but mayperform separate decoding using only the partial retransmission 1 h-15at the next TTI 1 h-10.

Further, although the retransmission is performed from the first symbolafter the control signal at the TTI 1 h-10 after the initialtransmission, the location of the retransmission may be variouslychanged to be applied.

Although the downlink transmission has been described as an example, theretransmission is also applicable to the uplink transmission. Asindicated in (b) and (c) in FIG. 1H, CB2 and CB3 among 6 initiallytransmitted CBs are retransmitted.

(1-1)-Th Embodiment

In accordance with an embodiment of the present disclosure, a method forconfiguring a piece of control information for transferring schedulinginformation or partial retransmission of data will be described withreference to FIGS. 1H, 1I, and 1J. Scheduling information provided inthis embodiment may be referred to as single-level control informationor single-stage control information.

Referring again to FIG. 1H, control information 1 h-01 and 1 h-09 istransmitted for scheduling of initial transmitted data 1 h-03 andpartial retransmission 1 h-15. The control information 1 h-01 and 1 h-09may include bit fields having a same size. The control information 1h-01 and 1 h-09 may include bit fields for the partial retransmission.The bit fields for the partial retransmission may be a CB groupindicator and a CB group NDI.

FIG. 1I illustrates an example bit configuration of a CB group indicatoraccording to an embodiment of the present disclosure.

Referring to FIG. 1I, the CB group indicator 1 i-01 may indicate CBsthat are included in one TB of data currently scheduled for downlinkdata transmission. If the scheduling is for uplink transmission, the CBgroup indicator may indicate the CBs that the terminal should transmitin one TB.

For example, FIG. 1I illustrates a CB group indicator 1 i-01 including 4bits 1 i-10, 1 i-11, 1 i-12, and 1 i-13. In mapping the CBS indicated bythe respective bits, a method provided according to the (1-3)-thembodiment below may be applied. Simply, for example, if one TB iscomposed of 4 CBs, information indicating one CB may be mapped onto onebit in order from the front. For example, if 4 bits 1 i-10, 1 i-11, 1i-12, and 1 i-30 of the CB group indicator 1 i-01 indicate 0110, secondand third CBs may be transmitted. If 4 bits 1 i-10, 1 i-11, 1 i-12, and1 i-30 of the CB group indicator 1 i-01 indicate 0000, the base stationand the terminal may determine that the corresponding transmissioncorresponds to an initial transmission.

FIG. 1J illustrates an example bit configuration of a CB group NDIaccording to an embodiment of the present disclosure.

Referring to FIG. 1J, the CB group NDI 1 j-03 may indicate whetherdecoding is performed using information of the initially transmitted CBor the currently transmitted CB by discarding the information of theinitially transmitted CB in decoding the currently received CB or CBgroups through downlink data transmission. The CB group NDI may not beincluded in the control information for uplink scheduling.

For example, FIG. 1J illustrates the CB group NDI 1 j-03 including bits1 j-20, 1 j-21, 1 j-22, and 1 j-23. In mapping the CB indicated byrespective bits, a method provided according to the (1-3)-th embodimentbelow may be applied. Simply, for example, if one TB is composed of 4CBs, information indicating one CB may be mapped onto one bit in orderfrom the front. For example, if 4 bits 1 j-20, 1 j-21, 1 j-22, and 1j-23 of the CB group NDI 1 j-03 indicate 0110, decoding may be performedusing currently received second and third CB portions by non-using ordiscarding the second and third CB information previously received indecoding the second and third CBs.

In analyzing the CB group NDI, the CB group NDI may be connected to theCB group indicator as described above because only partial CBs may betransmitted in the current retransmission, and therefore, the CB groupNDI may be effective only with respect to the currently retransmittedCBs. Accordingly, in decoding the CB or the CB group, if it isdetermined to discard the initially transmitted information,determination may be made by multiplying bits of respective componentsof the CB group NDI and the CB group indicator. When 4 CBs aretransmitted, e.g., if the CB group NDI is 0101 and the CB groupindicator is 0110, the terminal may determine that the second and thirdCBs are currently transmitted in accordance with the CB group indicator.In decoding the second CB in accordance with multiplication 0100 ofcomponents of the CB group NDI and the CB group indicator, decoding maybe performed by discarding the initially transmitted result, and indecoding the third CB, decoding may be performed together with theinitially transmitted result.

FIGS. 1KA to 1KD are flowcharts illustrating the operations of a basestation and a terminal that configure the CB group indicator and the CBgroup NDI. For convenience, explanation will be made based on downlinkdata transmission, and may also be applied to uplink data transmission.

FIG. 1KA is a flowchart illustrating a method for a base station toconfigure a bit field of a CB group indicator indicating whether totransmit a CB group in transmitting a TB.

Referring to FIG. 1KA, in step 1 k 1-02, the base station preparestransmission of a TB, and in step 1 k 1-04, determines whether the TBtransmission is an initial transmission.

If the TB is the initial transmission in step 1 k 1-04, all CB groupindicators are configured to 0 in step 1 k 1-06. However, if the TB isnot the initial transmission in step 1 k 1-04, the base stationdetermines whether a specific CB group is to be transmitted in step 1 k1-08.

If a specific CB group is to be transmitted, the corresponding bit ofthe CB group indicator is configured to 1 in step 1 k 1-10. However, ifa specific CB group is not to be transmitted, a corresponding bit of theCB group indicator is configured to 0 in step 1 k 1-12.

FIG. 1KB is a flowchart illustrating a method for a terminal to decodeCB groups by analyzing a bit field of a CB group indicator indicatingwhether to transmit a CB group in receiving a TB according to anembodiment of the present disclosure.

Referring to FIG. 1KB, in step 1 k 2-02, the terminal prepares forreception of a TB, and in step 1 k 2-04, determines whether CB groupindicators are all 0. If the CB group indicators are all 0, thetransmitted TB is identified as the initial transmission in step 1 k2-06. If the CB group indicators are not all 0, the terminal determineswhether a specific bit of the CB group indicator is 1 in step 1 k 2-08.If the specific bit of the CB group indicator is 1, the terminaldetermines that the corresponding CB group is transmitted, and decodesthe corresponding CB group in step 1 k 2-10. If the specific bit of theCB group is 0, the terminal determines that the corresponding CB groupis not transmitted, and the corresponding CB group is not decoded instep 1 k 2-12.

FIG. 1KC is a flowchart illustrating a method for a base station toconfigure a bit field of a CB group NDI so that an initial transmissionof a CB group previously transmitted is not to be used for terminaldecoding in transmitting a TB according to an embodiment of the presentdisclosure.

Referring to FIG. 1KC, the base station prepares for transmission of aTB in step 1 k 3-02, and determines whether to make the initialtransmission of a specific CB group be non-used for terminal decoding instep 1 k 3-04. If the base station determines to make the initialtransmission of a specific CB group be non-used for terminal decoding instep 1 k 3-04, in order for a terminal to perform decoding using only acurrently transmitted CB group, without using the base station initialtransmission of a specific CB group, a corresponding bit of a CB groupNDI is configured to 1 in step 1 k 3-06. If the base station determinesnot to make the initial transmission of a specific CB group be non-usedfor terminal decoding in step 1 k 3-04, i.e., the terminal is to performHARQ combining using the initial transmission of the specific CB groupand perform decoding of the currently transmitted CB group, thecorresponding bit of the CB group NDI is configured to 0 in step 1 k3-08.

FIG. 1KD is a flowchart illustrating a method for a terminal todetermine whether to use an initial transmission of a previouslytransmitted CB group for terminal decoding by confirming an NDI bitfield of a specific CB group according to an embodiment of the presentdisclosure.

Referring to FIG. 1KD, the terminal prepares for reception of a TB instep 1 k 4-02, and determines whether a specific bit of a CB group NDIis 1 in step 1 k 4-04. If the specific bit of the CB group NDI is 1 instep 1 k 4-04, the initial transmission of the corresponding CB group isnot used for decoding the current CB group in step 1 k 4-06. However, ifthe specific bit of the CB group NDI is 0 in step 1 k 4-04, HARQcombining is performed in order to use the initial transmission of thecorresponding CB group for decoding of the current CB group in step 1 k4-08.

Sizes of a bit field of a CB group indicator and an NDI bit field of theCB group may be preconfigured from the base station, or a determinedvalue may be used.

If the bit field of a CB group indicator and an NDI bit field of the CBgroup are included in control information, NDI information of the TB maybe omitted from the control information.

(1-1-1)-Th Embodiment

In accordance with an embodiment of the present disclosure a method isprovided for performing CB group unit retransmission while reducing thebit number of control information when configuring one piece of controlinformation for transferring scheduling information of partialretransmission of data. Further, CB group indication value (CIV)information may be included in the control information for partialretransmission. For example, the CIV information is not included in thecontrol information for an initial transmission or a fullretransmission, but is included in the control information for a partialretransmission. Further, the control information may include a one-bitindicator for indicating whether the control information is for aninitial transmission or full retransmission, or for a partialretransmission.

In a DCI for retransmission, it is possible to reduce resourceallocation for information bits. For example, increasing a resourceallocation unit value, as compared with that during the initialtransmission, when performing the partial retransmission, reduces theresource allocation for information bits. For example, in an initialtransmission, resource allocation information is transferred in 1 PRB,whereas in a retransmission, the resource allocation information istransferred in 4 PRBs. Accordingly, the number of bits of the resourceallocation information can be reduced, and as a result, may be used forthe CB group indicator.

For resource allocation, an RBG may be defined for resource allocation,and the resource allocation may be performed in a unit of the RBG.

TABLE 2 system bandwidth RBG size 1 RBG size 2 N_RB{circumflex over( )}DL P1 P2 <=10 1 2 11-26 2 4 27-63 3 6  64-112 4 8 112-224 8 16224-440 16 32

Table 2 is an example in which the RBG size according to the PRB numberincluded in a system bandwidth is defined. In Table 2, P1 is an RBGvalue used to configure the resource allocation information bitsincluded in the control information for the initial transmission or fullretransmission, and P2 is an RBG value used to configure the resourceallocation information bits included in the control information forpartial retransmission.

For example, if there are 400 PRBs in the system frequency band, 1 RBGincludes 16 PRBs in the initial transmission, and if resource allocationis made in a bit map method, 25-bit resource allocation information isnecessary in the initial transmission or the full retransmission.However, in the partial retransmission, 1 RBG includes 32 PRBs, and13-bit resource allocation information is necessary.

Accordingly, in the partial retransmission, as compared with the initialtransmission or full retransmission, bits of the resource allocationinformation may be reduced by 12 bits, and these 12 bits may be used asa 6-bit CB group indicator and a 6-bit CB group NDI, where one TB isdivided into 6 CB groups. Further, the 12 bits may be used to transfer12-bit CIV information, where one TB is divided into 7 CB groups. A1-bit partial retransmission indicator may be used to indicate whetherthe control information is for an initial transmission or fullretransmission, or a partial retransmission.

FIG. 1KE is a diagram illustrating methods of a base station and aterminal according to an embodiment of the present disclosure.

Referring to FIG. 1KE, the base station prepares downlink or uplinkscheduling in step 1 k 5-02, and determines whether the scheduling isfor an initial transmission or a TB-unit full retransmission in step 1 k5-04. If the scheduling is for the initial transmission or the fullretransmission, the base station configures resource allocationinformation by setting a partial retransmission indicator to 0 andselecting P1 as an RBG value, and includes the configured resourceallocation information in control information in step 1 k 5-06.

However, if the scheduling is for the partial retransmission, the basestation configures the resource allocation information by setting thepartial retransmission indicator to 1 and selecting P2 as the RBG, andincludes the CB group indicator and CB group NDI information in thecontrol information in step 1 k 5-08. Alternatively, the CB groupindicator and the CB group NDI may be replaced by a CIV value as will bedescribed below.

In step 1 k 5-12, the terminal decodes received control information.

In step 1 k 5-14, the terminal determines whether a partialretransmission indicator of a specific bit is 0.

If the partial retransmission indicator is 0, the terminal determinesthat the scheduling is for the initial transmission or the fullretransmission, and analyzes the resource allocation information byselecting a P1 value as the RBG in step 1 k 5-16. In step 1 k 5-18,transmission/reception is performed to follow the initial transmissionor the full retransmission.

However, if the partial retransmission indicator is 1 in step 1 k 5-14,the terminal determines that the corresponding control information isfor a partial retransmission, analyzes the resource allocationinformation by selecting a P2 value as the RBG, and analyzes the CBgroup indicator and the CB group NDI value in step 1 k 5-20.Alternatively, the CB group indicator and the CB group NDI may bereplaced by the CIV value, as will be described below.

The information indicated by the partial retransmission indicator valuemay differ depending on pre-engagement.

In the DCI for the retransmission, MCS and redundancy version (RV) bitsto be applied may be reduced. For example, while performing a partialretransmission, the MCS and the RV are selected in a limited range ascompared with those during performing the initial transmission, andthus, the MCS and RV bits can be reduced. For example, during theinitial transmission, all MCSs from QPSK to 256QAM can be selected,whereas during the retransmission, only MCSs within a predeterminedvalue of the MCSs used during the initial transmission may be selected.Accordingly, the number of bits for the MCS and RV can be reduced, andtherefore, may be used for the CB group indicator.

(1-1-2)-Th Embodiment

In accordance with an embodiment of the present disclosure, a method isprovided for inserting an indicator for discriminating between aninitial transmission and a partial retransmission, or an indicator fordiscriminating between a full retransmission and a partialretransmission, into control information for transferring schedulinginformation of the partial retransmission of data.

For example, if one DCI bit at a specific location is 0, the terminaldetermines that scheduling using the currently transferred DCI performsfull retransmission of one TB, and analyzes the received DCI as a DCIfor a full retransmission.

However, if one DCI bit at a specific location is 1, the terminaldetermines that scheduling using the currently transferred DCI performsretransmission in a unit of a CB group, and analyzes the received DCI asa DCI for a partial retransmission.

The above-described information may be transferred using one separatebit. For example, if the corresponding indicator is 0, it indicates afull retransmission, whereas if the corresponding indicator is 1, itindicates a partial retransmission.

The information may also be transferred using a 2-bit NDI value. Forexample, if the corresponding indicator is 00, it indicates an initialtransmission, and if the corresponding indicator is 01, it indicates afull retransmission. However, if the corresponding indicator is 10, itindicates a partial retransmission.

(1-1-3)-Th Embodiment

In accordance with an embodiment of the present disclosure, a method isprovided for inserting an indicator for discriminating between aninitial transmission and a partial retransmission, or an indicator fordiscriminating between a full retransmission and a partialretransmission into control information, where a CB group indicator anda CB group NDI are not transmitted from a base station to a terminal.

The above-described information may be transferred using one separatebit. For example, if the corresponding indicator is 0, it indicates afull retransmission, whereas if the corresponding indicator is 1, itindicates a partial retransmission.

The information may also be transferred using a 2-bit NDI value. Forexample, if the corresponding indicator is 00, the terminal maydetermine that it indicates an initial transmission, and if thecorresponding indicator is 01, it indicates a full retransmission.However, if the corresponding indicator is 10, the terminal maydetermine that it indicates a partial retransmission.

In the case of the full retransmission, corresponding TBs are allretransmitted, whereas in the case of the partial retransmission, onlyCB groups determined as NACK may be retransmitted in accordance withHARQ-ACK information of the CB group transferred from the terminal. Amethod for the terminal to transfer the HARQ-ACK information of the CBgroup may be performed as in the (1-4)-th embodiment, (1-5)-thembodiment, and (1-5-1)-th embodiment of the present disclosure.

(1-2)-Th Embodiment

In accordance with an embodiment of the present disclosure, a method isprovided for configuring two pieces of control information fortransferring scheduling information for a partial retransmission ofdata. A scheduling information provided in this embodiment may bereferred to as two-level control information or two-stage controlinformation.

FIG. 1L illustrates control information mapped for transmissionaccording to an embodiment of the present disclosure. Specifically, FIG.1L illustrates downlink data transmission, control signals DCI 1, andDCI 2 being transmitted, and data being mapped onto frequency-timeresources.

Referring to FIG. 1L, in a region pre-engaged between a base station anda terminal or a region configured by the base station, the controlsignal DCI 1 1 l-03 may be mapped to be transmitted. The DCI 1 1 l-03may include a carrier indicator field, resource block allocation,frequency hopping indicator, DCI format indicator, MCS value, RV value,NDI value, cyclic shift indicator to be used for DMRS, uplink index, SRSrequest indicator, resource allocation type indicator, and HARQ processnumber. In a part of the allocated resource block region indicated bythe DCI 1 1 l-03, the DCI 2 1 l-05 may be transmitted.

The DCI 2 1 l-05 may include a bit field of a CB group indicator and anNDI bit field of a CB group. Sizes of the bit field of the CB groupindicator and the NDI bit field of the CB group may be calculated fromcontrol information included in the DCI 1 1 l-03. For example, TBS maybe calculated from the number of allocated resource blocks and the MCSvalue, and the number of CBs or the number of CB groups may be knownfrom the predetermined or configured maximum length of the CB.Accordingly, the number of CBs or the number of CB groups may be thesizes of the bit field of the CB group indicator and the NDI bit fieldof the CB group.

For example, if the number of CBs calculated from the DCI 1 andpredetermined information is 4, the CB group indicator and the CB groupNDI are respectively composed of 4 bits. Accordingly, the terminal mayreceive the DCI 2, and may find out the CB group indicator and the CBgroup NDI information.

FIGS. 1KA to 1KD are flowcharts illustrating the operations of a basestation and a terminal that configure the CB group indicator and the CBgroup NDI. For convenience, explanation will be made based on downlinkdata transmission, and may also be applied to uplink data transmission.

FIG. 1KA is a flowchart illustrating a method for a base station toconfigure a bit field of a CB group indicator indicating whether totransmit the CB group in transmitting a TB. When preparing transmissionof a TB (1 k 1-02), the base station confirms whether the TBtransmission is an initial transmission (1 k 1-04). If the TB is theinitial transmission, all CB group indicators are configured to 0 (1 k1-06). If the TB is not the initial transmission, it is confirmedwhether a specific CB group is to be transmitted (1 k 1-08). If the CBgroup is transmitted, the corresponding bit of the CB group indicator isconfigured to 1 (1 k 1-10), whereas if the CB group is not transmitted,the corresponding bit of the CB group indicator is configured to 0 (1 k1-12).

FIG. 1KB is a flowchart illustrating a method for a terminal to decodeCB groups through analyzing of a bit field of a CB group indicatorindicating whether to transmit a CB group in receiving a TB. Whenpreparing reception of a TB (1 k 2-02), the terminal confirms whether CBgroup indicators are all 0 (1 k 2-04). If the CB group indicators areall 0, the transmitted TB is considered as the initial transmission (1 k2-06). If the CB group indicators are not all 0, it is confirmed whethera specific bit of the CB group indicator is 1 (1 k 2-08). If thespecific bit of the CB group indicator is 1, it is determined that thecorresponding CB group is transmitted, and decoding of the correspondingCB group is performed (1 k 2-10). If the specific bit of the CB group is0, it is determined that the corresponding CB group is not transmitted,and decoding of the corresponding CB group is not performed (1 k 2-12).

FIG. 1KC is a flowchart illustrating a method for a base station toconfigure a bit field of a CB group NDI so that the initial transmissionof the CB group previously transmitted is made not to be used forterminal decoding in transmitting the TB. When preparing transmission ofa TB (1 k 3-02), the base station determines whether to make the initialtransmission of a specific CB group be non-used for terminal decoding (1k 3-04). In order for a terminal to perform decoding using onlycurrently transmitted CB group without using the initial transmission ofthe specific CB group, the corresponding bit of the CB group NDI isconfigured to 1 (1 k 3-06). If the terminal performs HARQ combiningusing the initial transmission of the specific CB group and performsdecoding of the currently transmitted CB group, the corresponding bit ofthe CB group NDI is configured to 0 (1 k 3-08).

FIG. 1KD is a flowchart illustrating a method for a terminal todetermine whether to use the initial transmission of the previouslytransmitted CB group for terminal decoding through confirming of an NDIbit field of a specific CB group. When preparing reception of a TB (1 k4-02), the terminal confirms whether a specific bit of a CB group NDI is1 (1 k 4-04). If the specific bit of the CB group NDI is 1, the initialtransmission of the corresponding CB group is not used for decoding thecurrent CB group (1 k 4-06). If the specific bit of the CB group NDI is0, HARQ combining is performed in order to use the initial transmissionof the corresponding CB group for decoding of the current CB group (1 k4-08).

(1-2-1)-Th Embodiment

According to the (1-2-1)-th embodiment, a method for selecting a channelcoding applied to DCI 1 and DCI 2 in the (1-2)-th embodiment will bedescribed.

The base station configures bit fields of DCI 1 and applies a polarcode. A CRC may be added before the polar code is applied. Further, thebase station configures bit fields of DCI 2 and applies a Reed-Muller(RM) code or a block code. The base station can apply different channelcodes in accordance with the length of the bit field of DCI 2. If thebit field of DCI 2 is indicated as o_(n), a channel code output b_(i)may be calculated using Table 3 and Equation (1) below.

TABLE 3 i M_(i.0) M_(i.1) M_(i.2) M_(i.3) M_(i.4) M_(i.5) M_(i.6)M_(i.7) M_(i.8) M_(i.9) M_(i.10) 0 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 0 0 0 00 0 1 1 2 1 0 0 1 0 0 1 0 1 1 1 3 1 0 1 1 0 0 0 0 1 0 1 4 1 1 1 1 0 0 01 0 0 1 5 1 1 0 0 1 0 1 1 1 0 1 6 1 0 1 0 1 0 1 0 1 1 1 7 1 0 0 1 1 0 01 1 0 1 8 1 1 0 1 1 0 0 1 0 1 1 9 1 0 1 1 1 0 1 0 0 1 1 10 1 0 1 0 0 1 11 0 1 1 11 1 1 1 0 0 1 1 0 1 0 1 12 1 0 0 1 0 1 0 1 1 1 1 13 1 1 0 1 0 10 1 0 1 1 14 1 0 0 0 1 1 0 1 0 0 1 15 1 1 0 0 1 1 1 1 0 1 1 16 1 1 1 0 11 1 0 0 1 0 17 1 0 0 1 1 1 0 0 1 0 0 18 1 1 0 1 1 1 1 1 0 0 0 19 1 0 0 00 1 1 0 0 0 0 20 1 0 1 0 0 0 1 0 0 0 1 21 1 1 0 1 0 0 0 0 0 1 1 22 1 0 00 1 0 0 1 1 0 1 23 1 1 1 0 1 0 0 0 1 1 1 24 1 1 1 1 1 0 1 1 1 1 0 25 1 10 0 0 1 1 1 0 0 1 26 1 0 1 1 0 1 0 0 1 1 0 27 1 1 1 1 0 1 0 1 1 1 0 28 10 1 0 1 1 1 0 1 0 0 29 1 0 1 1 1 1 1 1 1 0 0 30 1 1 1 1 1 1 1 1 1 1 1 311 0 0 0 0 0 0 0 0 0 0

$\begin{matrix}{b_{i} = {\sum\limits_{n = 0}^{O - 1}\; {\left( {o_{n} \cdot M_{i,n}} \right){{mod}2}}}} & (1)\end{matrix}$

The terminal receives a control channel, and when decoding the controlinformation, performs decoding through application of different channelcodes in accordance with DCI 1 and DCI 2. That is, for decoding DCI 1,the terminal uses a decoder for the polar code, and for decoding DCI 2,the terminal uses a decoder for the block code or the RM code.

FIG. 1MA is a flowchart illustrating a method for a base station toapply a channel code based on a control information type according to anembodiment of the present disclosure.

Referring to the FIG. 1MA, a base station prepares control informationbit field (1 m 1-02), and determines whether a format of the controlinformation is DCI 1 (1 m 1-04). If the base station determines theformat is not DCI 1, the base station applies a block code or a RM codeto the bit field composed of a CB group indicator and a CP group NDI (1m 1-08). If the base station determines the format is DCI 1, the basestation adds CRC to the bit field composed of CIF, resource allocation,MCS, RV, and HARQ process number and applies a polar code to the bitfield (1 m 1-06).

FIG. 1MB is a flowchart illustrating a method for a terminal to performchannel code decoding based on a control information type according toan embodiment of the present disclosure.

Referring to the FIG. 1MB, the terminal prepares decoding controlinformation (1 m 2-02) and determines whether a format of the controlinformation is DCI 1 (1 m 2-04). If the terminal determines the formatis not DCI 1, the terminal performs decoding by using a decoder of ablock code or a RM code, and confirms CB group indicator and CB groupNDI from the bit field (1 m 2-08). If the terminal determines the formatis DCI 1, the terminal performs decoding by using a polar code,determines transmission succeed/failure through CRC checking, andconfirms the control information from the bit field (1 m 2-06).

Although FIGS. 1MA and 1MB illustrate that a polar code is applied toDCI 1 and an RM code is applied to DCI 2, they may be generalized by amethod for applying a first channel code and a second channel code.Alternatively, the polar code may be used as the first channel codeapplied to DCI 1, and a repetition code may be used as the secondchannel code applied to DCI 2.

(1-2-2)-Th Embodiment

In accordance with an embodiment of the present disclosure, one of a bitfield of the CB group indicator and an NDI bit field of the CB group maybe omitted from the control information based on the configuration ofthe base station.

For example, when the CB group NDI is omitted and the CB group indicatoris used. During a partial retransmission, a base station may retransmitonly specific CB groups, and may transfer to the terminal information onthe CB groups that are being used for retransmission through the CBgroup indicator. The terminal and the base station may previouslydetermine whether to perform decoding with respect to the CB groupsreceived through partial retransmission, after performing HARQ combiningof the initial transmission, or to perform decoding using only data ofthe newly received CB groups by discarding data of the corresponding CBgroups received during the initial transmission.

For example, the terminal and the base station may predetermine toalways perform decoding using only data of the newly received CB groupswhile discarding the data of the corresponding CB groups indicated bythe CB group indicator received during the initial transmission whilethe partial retransmission is performed. Further, the base station mayconfigure the terminal, through upper signaling, as to whether toperform decoding with respect to the CB groups received through thepartial retransmission, after performing the HARQ combining of theinitial transmission, or to perform decoding using only data of thenewly received CB groups by discarding the data of the corresponding CBgroups received during the initial transmission.

(1-2-3)-Th Embodiment

In accordance with an embodiment of the present disclosure, a method isprovided, in which a bit field of a CB group indicator and an NDI bitfield of a CB group are included in one field to be simultaneouslyanalyzed in control information based on the configuration of the basestation. Specifically, a CB group indication value (CIV) is introduced,and through one CIV value, the CB group indicator and the CB group NDIinformation as described above according to the (1-1)-the embodiment orthe (1-2)-th embodiment are transferred, will be described. As describedabove, if the CIV information is transferred from one piece of controlinformation, the NDI information of a TB may be omitted.

For example, the CIV value may be determined as follows.

Three scenarios are considered, 1) one CB group is not retransmitted, 2)the terminal performs decoding of the corresponding CB group using onlynewly received portion while discarding the data for the initialtransmission even if the retransmission is performed, or 3) the terminalperforms decoding through performing HARQ combining with respect to theretransmitted portion and the initially transmitted portion after theretransmission is performed.

Accordingly, if it is assumed that N CB groups in total are transmittedduring the initial transmission, the number of cases that the terminalshould consider when the retransmission is performed may be 3{circumflexover ( )}(N)−1 (or 3N-1), because a control signal in accordance withthe retransmission will not be transferred when N CB groups exist, eachgroup has three kinds of cases, and all the CB groups are notretransmitted. Accordingly, the number of cases 3N-1 to be considered bythe terminal may be expressed as an N-digit ternary number.

For example, if 4 CB groups exist, the CIV value may be expressed as0120(3). In the above case, X(3) indicates X as a ternary number.

In the above-described example, 0 at each digit indicates that thecorresponding CB group has not been retransmitted, and 1 at each digitindicates that decoding should be performed using only newly receivedportion while discarding the data for the initial transmission, althoughthe corresponding CB group has been retransmitted. Further, 2 at eachdigit may indicate that HARQ combining should be performed with respectto the retransmitted portion and the initially transmitted portion whenthe corresponding CB group has been retransmitted.

Accordingly, 0120(3) indicates to perform decoding using only data ofthe second retransmitted CB group while discarding the data of thesecond CB group initially transmitted, where first and fourth CB groupsare not retransmitted, but the second CB group is retransmitted, and mayindicate that the third CB group is retransmitted, and that decoding canbe performed by performing HARQ combining with respect to theretransmitted portion and the initially transmitted portion.

Accordingly, the number of cases that the terminal should consider from0001(3) to 2222(3) is 34−1=80 in total. That is, the CIV value can beexpressed by a 4-digit ternary number, and the CIV value determined, asshown above, may be converted into a binary number to be inserted into abit field of control information. That is, if 4 CB groups exist, and 4bits of the CB group indicator and 4 bits of the CB group NDI arerequired, a total of 8 bits are required. However, using theabove-described CIV value, a total of 7 bits are required for 80 cases.As described above, the CIV value may be directly converted into abinary number, or the CIV-1 value may be converted into a binary numberto be included in the control information.

If CIV=0120(3) is converted into a 7-digit binary number, it becomesCIV=0001111(2). Accordingly, 0001111 may be included in the controlinformation.

Further, the CIV-1 value may be converted into a binary number, and0001110 may be included in the control information.

If the control information is received, the terminal identifies theabove-described CIV value, and converts the CIV value into a ternarynumber, in order to determine transmission information for therespective CB groups.

The above-described method is merely exemplary to define the CIV value,and the CIV value may be defined by other methods. For example, two CBgroups can be defined as shown in Table 4 below.

TABLE 4 CIV First CB group Second CB group 0 Initial transmissionInitial transmission 1 Initial transmission Retransmission 2 Initialtransmission Non-transmission 3 Retransmission Initial transmission 4Retransmission Retransmission 5 Retransmission Non-transmission 6Non-transmission Initial transmission 7 Non-transmission Retransmission

Using Table 4, if there is data previously received by the terminal forthe corresponding CB group, the initial transmission may indicate toperform decoding using only newly received portion while discarding thepreviously received portion, and retransmission may indicate to performdecoding together with the data previously received for thecorresponding CB group. Non-transmission may indicate that thecorresponding CB group is not currently transmitted. Accordingly, inTable 4, for CIV=1, the first CB group may indicate that if the terminalreceives the first CB group, the corresponding CB group is to be decodedusing only a newly received portion while the previous reception portionis discarded, and the second CB group may indicate that thecorresponding CB group is to be decoded by performing HARQ combiningtogether with the previously received portion. Table 4 may be modifiedin various methods and may be applied to define the CIV information.

(1-3)-Th Embodiment

In accordance with an embodiment of the present disclosure, a method isprovided for configuring a CB indicator and a CB NDI bit field includedin control information.

The number M of code block groups may be upper-signaled from the basestation to the terminal, or information on an M value may be transferredto the DCI. Further, the number M may be automatically determined inaccordance with the number of code blocks included in the TBS, TB, orsystem frequency bands. For example, the number M of code block groupsmay be determined in accordance with the TBS value of the scheduled datathrough the TBS as shown in Table 5 below.

TABLE 5 TBS value M TBS < 61,440 1 61,440 < TBS < 122,880 2 122,880 <TBS < 184,320 3 184,320 < TBS < 245,760 4

Table 5 illustrates a scenario where the TBS value is smaller than245,760, but is not limited thereto. The M value may be defined evenwith respect to a larger TBS value using a similar rule.

As another example, the M value may be determined in accordance with thesystem frequency band, assuming that the unit of the frequency resourceis a resource block. The resource block corresponds to 180 kHz in theLTE system, and although the resource block corresponds to 12subcarriers, it can be differently determined in the NR or 5G system.For example, one resource block may be a frequency band corresponding to375 kHz. In accordance with the total number of resource blocks in thesystem frequency band, the M value may differ as shown in Table 6 below.

TABLE 6 Total number of resource blocks in system frequency band M <=101 11-26 2 27-63 3  64-110 4

If transmission of several code blocks has failed after one TB isinitially transmitted, a transmission end (e.g., a base station) mayperform transmission only with respect to the failed code blocks whenretransmission is performed. When the code block is transmitted duringthe retransmission, code block index information may be included in thecode block to be transmitted. Accordingly, if data corresponding to theretransmission is received, a reception end may confirm the code blockindex information, and then perform decoding through combining with theinitial transmission in decoding the corresponding code block.

After the number M of the CB groups is determined, respective CBs areincluded in the groups in due order.

For example, if the total number of CBs is C, K₊ and K⁻ associated withCB groups can be calculated as shown in Equation (2).

K ₊ =C−└C/M┘·M

K ⁻ =M−K ₊  (2)

From the front, K₊ CB groups include ┌C/M┐ CBs, and the remaining K⁻ CBgroups include └C/M┘ CBs.

After configuring the C CBs to M CB groups, a CB group indicator and aCB group NDI having M-bit bit fields, respectively, may be generated.The n-th bit of the CB group indicator indicates the CBs belonging tothe n-th CB group, and the m-th bit of the CB group NDI indicates theCBs belonging to the m-th CB group. Accordingly, the base station andthe terminal may perform the methods as described above with referenceto FIGS. 1KA, 1KB, 1KC, and 1KD.

For example, if C is 15 and M is 4, K₊ becomes 3, and K⁻ becomes 1. Thatis, 3 CB groups include ┌C/M┐=┌15/4┐=4 CBs, and one CB group includes└C/M┘=└15/4┘=3 CBs. Accordingly, CB 1 to CB 4 belong to CB group 1, andCB 5 to CB 8 belong to CB group 2. Further, CB 9 to CB 12 belong to CBgroup 3, and CB 13 to CB 15 belong to CB group 4. Although the CBs aresuccessively included in the CB group in the description above, they maybe modified to be included in the CB group in accordance with a specificrule.

Although a method has been described, in which the reception endperforms feedback of whether the transmission of the code block hasfailed, and the transmission end performs partial retransmission of thecode blocks, it is not necessary to always perform both operations incombination, and they may be separately used.

In accordance with an embodiment of the present disclosure, an initialtransmission and a retransmission may indicate an initial transmissionand a retransmission in a HARQ operation.

(1-4)-Th Embodiment

Accordingly, a method will be described for a terminal to send HARQ-ACKfeedback to a base station, when the terminal to which partialretransmission has been configured receives downlink transmission. Inorder to generate the HARQ-ACK information in a unit of a CB group, theterminal configures one or more bits.

Like the method for determining the M as described above, a bit fieldhaving the same size as the number M of CB groups is configured, thebits of the bit field may be used as information indicating whether thetransmission of the respective CB groups has succeeded, and the bitfield may be transferred from the terminal to the base station to beused as the HARQ-ACK feedback information.

For example, if the number of CBs C is 15 and M is 4, K₊ becomes 3, andK⁻ becomes 1. That is, 3 CB groups include └C/M┐=└15/4┐=4 CBs, and oneCB group includes └C/M┘=└15/4┘=3 CBs. Accordingly, CB 1 to CB 4 belongto CB group 1, and CB 5 to CB 8 belong to CB group 2. Further, CB 9 toCB 12 belong to CB group 3, and CB 13 to CB 15 belong to CB group 4.That is, the terminal transmits M-bit HARQ-ACK feedback to the basestation using an uplink control channel. If transmission of CB group ihas succeeded, the i-th bit is set to 1 in the M-bit HARQ-ACK feedback,and if transmission of CB group i has failed, the i-th bit is set to 0in the M-bit HARQ-ACK feedback.

This method is also applicable for a terminal to which partialretransmission has been configured to transmit uplink data, and a basestation to send the HARQ-ACK feedback to the terminal.

(1-5)-Th Embodiment

According to an embodiment of the present disclosure, a method isprovided for a terminal to send an HARQ-ACK when transmission of partialCB groups has failed during the initial transmission and retransmissionis performed where the terminal to which partial retransmission has beenconfigured receives downlink data.

When the terminal to which partial retransmission has been configuredreceives the downlink data, the HARQ-ACK feedback for the initialtransmission may be performed as described above. If transmission of thepartial CB groups has failed during the initial transmission, and thepartial retransmission is performed only with respect to thetransmission-failed CB groups, the terminal may transmit only theHARQ-ACK bits for the transmitted CB groups to the base station.

For example, if the number C of CBs transmitted during the initialtransmission is 15, and M is 4, the terminal may perform the HARQ-ACKtransmission for the initial transmission as described above. Forexample, if the terminal sends the base station feedback of thetransmission failure of CB group 2 and CB group 3, the base station caninclude only CB group 2 and CB group 3 in the retransmission to betransmitted. Even if the terminal sends the base station feedback of thetransmission failure of CB group 2 and CB group 3, it may be possiblefor the base station to retransmit all CB groups in accordance with thejudgment of the base station. In this example, a base station includesonly CB group 2 and CB group 3 in the retransmission. Accordingly,during the retransmission, only CB group 2 and CB group 3 are includedin the retransmission, and a CB group indicator may indicate 0110.

For HARQ-ACK feedback for a partial retransmission, the terminal mayconfigure a bit field, the size of which is different from the size ofthe bit field of the CB group indicator, but is the same as the sizecorresponding to the number of CB groups to be partially retransmitted,and transmit the bit field to the base station as the uplink controlsignal. For example, if only CB group 2 and CB group 3 are included inthe retransmission, a 2-bit HARQ-ACK bit field is prepared, in whichinformation on whether retransmitted CB group 2 has succeeded isconfigured to the first bit, and information on whether retransmitted CBgroup 3 has succeeded is configured to be transmitted to the basestation.

(1-5-1)-Th Embodiment

According to an embodiment of the present disclosure, another method isprovided for a terminal to send an HARQ-ACK when transmission of partialCB groups has failed during the initial transmission and retransmissionis performed, where the terminal to which partial retransmission hasbeen configured receives downlink data.

When the terminal to which partial retransmission has been configuredreceives the downlink data, the HARQ-ACK feedback for the initialtransmission may be performed as described above. If transmission of thepartial CB groups has failed during the initial transmission, and thepartial retransmission is performed only with respect to thetransmission-failed CB groups, the terminal may reorganize M transmittedCB groups, and transmit, to the base station, HARQ-ACK bits having thesame size as that of the HARQ-ACK bit for the initial transmission forthe transmitted CB groups to the base station.

For example, if the number C of CBs transmitted during the initialtransmission is 15, and M is 4, the terminal may perform the HARQ-ACKtransmission for the initial transmission as described above.

For example, if the terminal sends the base station feedback of thetransmission failure of CB group 2 and CB group 3, the base station caninclude only CB group 2 and CB group 3 in the retransmission to betransmitted. Even if the terminal sends the base station feedback of thetransmission failure of CB group 2 and CB group 3, it may be possiblefor the base station to retransmit all CB groups in accordance with thejudgment of the base station. In this example, the base station includesonly CB group 2 and CB group 3 in the retransmission. Accordingly,during the retransmission, only CB group 2 and CB group 3 are includedin the retransmission, and a CB group indicator may indicate 0110.

The HARQ-ACK feedback for the partial retransmission includes a bitfield having the same size as the bit field of a CB group indicator, andfor this, the terminal may reorganize 4 CB groups. Since each of CBgroup 2 and CB group 3 include 4 CBs, 8 CBs are retransmitted in total.In order to organize 8 CBs into new CB groups, two CBs may be includedin one CB group. Accordingly, the terminal prepares a 4-bit HARQ-ACK,and whether transmission of the first and second CBs among 8retransmitted CBs has succeeded is configured to the first HARQ-ACK, andwhether transmission of the third and fourth CBs has succeeded isconfigured to the second HARQ-ACK. Whether transmission of the fifth andsixth CBs has succeeded is configured to the third HARQ-ACK, and whethertransmission of the seventh and eighth CBs has succeeded is configuredto the fourth HARQ-ACK to be transmitted to the base station.

If retransmission for the partial retransmission is needed again, thebase station may be able to perform retransmission per newly configuredCB group.

(1-6)-Th Embodiment

The first to sixth embodiments refer to a reception method for aterminal using an HARQ process through the initial transmission, thewhole TB retransmission, the whole CB retransmission during downlinktransmission.

For respective received TBs and related HARQ operation information, aHARQ process may perform the following operations.

-   -   If an NDI value is a value different from a previous value, for        a process for broadcasting, for a process for transmitting        system information, or first received data, the received data is        considered as an initial transmission.    -   If a CB group indicator and a CB group NDI are disabled or are        not transferred in another embodiment, the received data is        considered as an entire TB retransmission.    -   If CB group indicators are all 0 or CB group NDIs all indicate 0        in another embodiment, the received data is considered as an        entire TB retransmission.    -   The received data is considered as CB group partial        retransmission.

The terminal may perform the following operations.

-   -   If the received data corresponds to an initial transmission,        decoding of received data is performed.    -   If a TB corresponding to received data is not successfully        decoded, where the received data corresponds to an entire TB        retransmission, the received data and the corresponding TB data        of a soft buffer are combined, and decoding of the combined data        is performed. The data combining may be performed by combining        log-likelihood ratio (LLR) values.    -   If a TB corresponding to received data is not successfully        decoded, where the received data corresponds to a CB group        partial retransmission, a portion corresponding to a CB group in        which both a CB group indicator and a CB group NDI indicate 1 is        combined with the corresponding portion stored in the existing        soft buffer, and a portion corresponding to a CB group in which        the CB group indicator indicates 1, but the CB group NDI        indicates 0 is replaced by a newly received portion while the        corresponding portion stored in the existing soft buffer is        discarded, and decoding of the combined or replaced data is        performed.

If decoding of the data performed for the corresponding TB hassucceeded, or the previous decoding of the corresponding TB hassucceeded, the terminal performs the following operation.

-   -   If a HARQ process is for broadcasting, a decoded MAC PDU is        transferred to an upper layer.    -   If a HARQ process is not for broadcasting and data decoding for        the corresponding TB has first succeeded, a decoded MAC PDU is        transferred to a place for dissolving and demultiplexing.    -   An ACK for the corresponding TB is generated.

If data decoding performed for a corresponding TB has not succeeded, anda previous decoding of the corresponding TB has not succeeded, aterminal performs the following operations.

-   -   Data of a soft buffer for the corresponding TB is replaced by        data of which the decoding has been performed by the terminal.    -   A NACK for the corresponding TB is generated.

A MAC layer does not transfer the generated ACK or NACK to a physicallayer if the HARQ process corresponds to a temporary C-RNTI value or atemporary terminal ID value, if contention resolution has not yetsucceeded, if the HARQ process is a process for broadcasting, or if atimer for controlling a timing advance (TA) value is stopped or expires.Alternatively, the generated ACK or NACK is transferred from the MAClayer to the physical layer.

In order to perform the above-described embodiments of the presentdisclosure, a transmitter, a receiver, and a processor of a terminal ora base station are illustrated in FIG. 1N and FIG. 1O. Atransmission/reception method for a base station or a terminal isprovided to determine and receive control information for partialretransmission according to the (1-1)-th to (1-6)-th embodiments, andfor this, the receiver, the processor, and the transmitter of the basestation or the terminal should operate according to the respectiveembodiments.

FIG. 1N illustrates a terminal according to an embodiment of the presentdisclosure. Specifically, the terminal in FIG. 1N may perform theabove-described methods.

Referring to FIG. 1N, the terminal includes a receiver 1 n-00, atransmitter 1 n-04, and a processor 1 n-02.

Alternatively, the receiver 1 n-00 and the transmitter 1 n-04 may becombined in a transceiver, which transmits/receives signals to/from thebase station. The signals may include control information and data. Forexample, the transceiver may include an RF transmitter up-converting andamplifying the frequency of a transmitted signal, and an RF receiverlow-noise-amplifying the received signal and down-converting thefrequency of the amplified signal.

Further, the transceiver may receive a signal through a radio channel,output the signal to the processor 1 n-02, and transmit the signaloutput from the processor 1 n-02 through the radio channel. Theprocessor 1 n-02 may control a series of processes so that the terminalcan operate according to the above-described embodiments of the presentdisclosure. For example, when receiving the data signal from the basestation, the receiver 1 n-00 may receive a CB group indicator, a CBgroup NDI, and data, and the processor 1 n-02 may perform data decodingin accordance with the CB group indicator and the CB group NDI.Thereafter, the transmitter 1 n-04 may transmit HARQ-ACK informationthat follows the CB group to the base station.

FIG. 1O illustrates a base station according to an embodiment of thepresent disclosure. Specifically, the base station in FIG. 1O mayperform the above-described methods.

Referring to FIG. 1O, the base station includes a receiver 1 o-01, atransmitter 1 o-05, and a processor 1 o-03.

Alternatively, the receiver 1 o-01 and the transmitter 1 o-05 may becombined in a transceiver, which transmits/receives signals to/from theterminal. As described above, the signals may include controlinformation and data. For example, the transceiver may include an RFtransmitter up-converting and amplifying the frequency of a transmittedsignal, and an RF receiver low-noise-amplifying the received signal anddown-converting the frequency of the amplified signal.

Further, the transceiver may receive the signal through a radio channel,output the signal to the processor 1 o-03, and transmit the signaloutput from the processor 1 o-03 through the radio channel. Theprocessor 1 o-03 may control a series of processes so that the basestation can operate according to the above-described embodiments of thepresent disclosure.

For example, the processor 1 o-03 may operate to determine whether toinsert a CB group indicator and a CB group NDI, and to generate the CBgroup indicator, the CB group NDI information, and corresponding data tobe transferred to the terminal. Thereafter, the transmitter 1 o-05transmits control information including the CB group indicator and theCB group NDI, and the receiver 1 o-01 receives feedback information fromeach CB group for which the transmission has succeeded.

Further, the processor 1 o-03 may operate to generate DCI including a CBgroup indicator and a CB group NDI information, or an upper signalingsignal. The DCI or the upper signaling may indicate whether code blockindex information is included in the scheduled signal.

Second Embodiment

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings.

In explaining the embodiments, explanation of technical contents whichare well known in the art to which the present disclosure pertains andare not directly related to the present disclosure will be omitted. Thisis to transfer the subject matter of the present disclosure more clearlywithout obscuring the same through omission of unnecessary explanations.

For the same reason, in the accompanying drawings, sizes and relativesizes of some constituent elements may be exaggerated, omitted, orbriefly illustrated. Further, sizes of the respective constituentelements do not completely reflect the actual sizes thereof. In thedrawings, the same drawing reference numerals are used for the same orcorresponding elements across various figures.

The aspects and features of the present disclosure and methods forachieving the aspects and features will be apparent by referring to theembodiments to be described in detail with reference to the accompanyingdrawings. However, the present disclosure is not limited to theembodiments disclosed hereinafter, but can be implemented in diverseforms. The matters defined in the description, such as the detailedconstruction and elements, are nothing but specific details provided toassist those of ordinary skill in the art in a comprehensiveunderstanding of the disclosure, and the present disclosure is onlydefined within the scope of the appended claims. In the entiredescription of the present disclosure, the same drawing referencenumerals are used for the same elements across various figures.

In this case, it will be understood that each block of the flowchartillustrations, and combinations of blocks in the flowchartillustrations, can be implemented by computer program instructions.These computer program instructions can be provided to a processor of ageneral purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions specified in the flowchart block or blocks.

These computer program instructions may also be stored in a computerusable or computer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer usable orcomputer-readable memory produce an article of manufacture includinginstruction means that implement the function specified in the flowchartblock or blocks. The computer program instructions may also be loadedonto a computer or other programmable data processing apparatus to causea series of operational steps to be performed on the computer or otherprogrammable apparatus to produce a computer implemented process suchthat the instructions that execute on the computer or other programmableapparatus provide steps for implementing the functions specified in theflowchart block or blocks.

Also, each block of the flowchart illustrations may represent a module,segment, or portion of code, which includes one or more executableinstructions for implementing the specified logical function(s). Itshould also be noted that in some alternative implementations, thefunctions noted in the blocks may occur out of the order. For example,two blocks shown in succession may in fact be executed substantiallyconcurrently or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved.

In this case, the term “˜unit”, as used in an embodiment, means, but isnot limited to, a software or hardware component, such as FPGA or ASIC,which performs certain tasks. However, “˜unit” does not mean to belimited to software or hardware. The term “˜unit” may advantageously beconfigured to reside on the addressable storage medium and configured toexecute on one or more processors. Thus, “˜unit” may include, by way ofexample, components, such as software components, object-orientedsoftware components, class components and task components, processes,functions, attributes, procedures, subroutines, segments of programcode, drivers, firmware, microcode, circuitry, data, databases, datastructures, tables, arrays, and variables. The functionality providedfor in the components and “˜units” may be combined into fewer componentsand “˜units” or further separated into additional components and“˜units”. Further, the components and “˜units” may be implemented tooperate one or more CPUs in a device or a security multimedia card.Also, in the embodiments, “˜unit” may include one or more processors.

A wireless communication system has escaped from an initialvoice-oriented service providing system, and has been developed as abroadband wireless communication system that provides high-speed andhigh-quality packet data services in accordance with the communicationstandards, such as high speed packet access (HSPA) of 3GPP, long termevolution (LTE) or evolved universal terrestrial radio access (E-UTRA),LTE-advanced (LTE-A), high rate packet data (HRPD) of 3GPP2,ultra-mobile broadband (UMB), and 802.16e of IEEE. Further, for the 5Gwireless communication system, 5G or new radio (NR) communicationstandards have been made.

In the wireless communication system including 5G as described above, atleast one service of enhanced mobile broadband (eMBB), massive machinetype communications (mMTC), and ultra-reliable and low-latencycommunications (URLLC) may be provided to the terminal. Hereinafter, inall embodiments of the present disclosure, the eMBB may be a serviceaiming at high-speed transmission of high-capacity data, the mMTC may bea service aiming at minimization of a terminal power and connection ofmultiple terminals, and the URLLC may be a service aiming atultra-reliability and low latency, but are not limited thereto. Further,in all embodiments of the present disclosure, it is assumed that theURLLC service transmission time is shorter than the eMBB or mMTC servicetransmission time, but is not limited thereto. The three kinds ofservices as described above may be important scenarios in an LTE systemor 5G/new radio or next radio (NR) system beyond LTE.

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings. In describing thepresent disclosure, a detailed description of related known functions orconfigurations will be omitted if it is determined that it obscures thedisclosure in unnecessary detail. Further, all terms used in thedescription are general terms that are widely used in consideration oftheir functions in the present disclosure, but may differ depending onintentions of a user or an operator, or customs. Accordingly, theyshould be defined based on the contents of the whole description of thepresent disclosure. Hereinafter, a base station is a subject thatperforms resource allocation to a terminal, and may be at least one ofan eNode B (or eNB), gNode B (or gNB), Node B, base station (BS), radioconnection unit, base station controller, and node on a network. Theterminal may include user equipment (UE), mobile station (MS), cellularphone, smart phone, computer, or multimedia system capable of performinga communication function.

In the present disclosure, a downlink (DL) is a radio transmission pathof a signal that is transmitted from the base station to the terminal,and an uplink (UL) means a radio transmission path of a signal that istransmitted from the terminal to the base station. Also, embodiments ofthe present disclosure to be described hereinafter may also be appliedto other communication systems having similar technical backgrounds orchannel types. Further, the embodiments of the present disclosure mayalso be applied to other communication systems through partialmodifications thereof in a range that does not greatly deviate from thescope of the present disclosure through the judgment of those skilled inthe art.

In an LTE system that is a representative example of the broadbandwireless communication system, an orthogonal frequency divisionmultiplexing (OFDM) method is adapted for a downlink (DL), and a singlecarrier frequency division multiple access (SC-FDMA) method is adaptedfor an uplink (UL). The uplink means a radio link through which aterminal (user equipment (UE) or mobile station (MS)) transmits data ora control signal to a base station (BS or eNode B), and the downlinkmeans a radio link through which the base station transmits data or acontrol signal to the terminal. In general, the multiple access methodas described above may separate data and control information from eachother for each user by allocating and operating time-frequency resourceson which the data or the control information is carried for each user sothat the resources do not overlap each other, that is, so that theorthogonality is realized.

The LTE system adapts a hybrid automatic repeat request (HARQ) method inwhich a physical layer re-transmits the corresponding data if a decodingfailure occurs during initial transmission. The HARQ method enables areceiver to transmit information (negative acknowledgement (NACK)) fornotifying a transmitter of the decoding failure if the receiver couldnot accurately decode the data, so that the transmitter can re-transmitthe corresponding data on the physical layer. The receiver combines thedata re-transmitted by the transmitter with the previous data of whichthe decoding has failed to heighten data reception performance. Further,if the receiver has accurately decoded the data, it transmitsinformation (acknowledgement (ACK)) for notifying the transmitter of adecoding success, so that the transmitter can transmit new data.

FIG. 2A is a diagram illustrating the basic structure of atime-frequency domain that is a radio resource region from which data ora control channel is transmitted through a downlink in an LTE system.

In FIG. 2A, a horizontal axis represents a time domain, and a verticalaxis represents a frequency domain. In the time domain, the minimumtransmission unit is an OFDM symbol, and N_(symb) OFDM symbols 2 a-02are gathered to constitute one slot 2 a-06, and two slots are gatheredto constitute one subframe 2 a-05. The length of the slot is 0.5 ms, andthe length of the subframe is 0.1 ms. Further, the radio frame 2 a-14 isa time domain interval composed of 10 subframes. The minimumtransmission unit in the frequency domain is a subcarrier, and thetransmission bandwidth of the whole system is composed of N_(BW)subcarriers 2 a-04 in total.

In the time-frequency domain, the basic unit of a resource is a resourceelement (RE) 2 a-12, and it may be indicated as an OFDM symbol index anda subcarrier index. A resource block (RB) 2 a-08 or a physical resourceblock (PRB) is defined as N_(symb) successive OFDM symbols 2 a-02 in thetime domain and N_(RB) successive subcarriers 2 a-10 in the frequencydomain. Accordingly, one RB 2 a-08 is composed of N_(symb)×N_(RB) REs 2a-12. In general, the minimum transmission unit of data is the RB unitas described above. In the LTE system, it is general that N_(symb) isN_(symb)=7, N_(RB) is N_(RB)=12, and N_(BW) and N_(RB) are in proportionto the system transmission bandwidth.

The data rate is increased in proportion to the number of RBs beingscheduled to a terminal. In the LTE system, 6 transmission bandwidthsare defined and operated. In the case of an FDD system that divides andoperates a downlink and an uplink through a frequency, the transmissionbandwidth of the downlink and the transmission bandwidth of the uplinkmay differ from each other. The channel bandwidth indicates an RFbandwidth that corresponds to the system transmission bandwidth. Table1A presents a corresponding relationship between the system transmissionbandwidth defined in the LTE system and the channel bandwidth. Forexample, in the LTE system having the channel bandwidth of 10 MHz, thetransmission bandwidth is composed of 50 RBs.

TABLE 7 Channel bandwidth BW_(Channel) [MHZ] 1.4 3 5 10 15 20Transmission 6 15 25 50 75 100 bandwidth configurationtion N_(RB)

In the case of downlink control information, it is transmitted withinthe first N OFDM symbols in the subframe. In general, the number N isN={1, 2, 3}. Accordingly, in accordance with the amount of controlinformation to be transmitted in the current subframe, the value N maybe varied for each subframe. The control information includes a controlchannel transmission interval indicator indicating how many OFDM symbolsthe control information is transmitted through, scheduling informationon downlink data or uplink data, and a HARQ ACK/NACK signal.

In the LTE system, the scheduling information on the downlink data orthe uplink data is transferred from the base station to the terminalthrough downlink control information (DCI). The uplink (UL) means aradio link through which the terminal transmits data or a control signalto the base station, and the downlink (DL) means a radio link throughwhich the base station transmits data or a control signal to theterminal.

The DCI is defined in accordance with various formats, and applies andoperates a determined DCI format in accordance with whether thescheduling information is uplink data scheduling information (UL grant)or downlink data scheduling information (DL grant), whether the DCI iscompact DCI having a small size of control information, whether spatialmultiplexing using multiple antennas is applied, or whether the DCI isDCI for power control. For example, DCI format 1 that is the schedulingcontrol information (DL grant) of the downlink data may include at leastone of the following control information.

-   -   Resource allocation type 0/1 flag: This is to notify whether a        resource allocation type is type 0 or type 1. The type 0        allocates resources in the unit of a resource block group (RBG)        through applying of a bitmap type. In the LTE system, the basic        unit for scheduling is a resource block (RB) that is expressed        as a time and frequency domain resource, and the RBG is composed        of a plurality of RBs to be considered as the basic unit for        scheduling in the type 0. The type 1 allocates a specific RB in        the RBG.    -   Resource block assignment: This notifies of the RB that is        allocated for data transmission. The expressed resource is        determined in accordance with the system bandwidth and the        resource allocation method.    -   Modulation and coding scheme (MCS): This notifies of a        modulation method used for data transmission and the size of a        transport block that is data to be transmitted.    -   HARQ process number: This notifies of the process number of        HARQ.    -   New data indicator: This notifies of whether HARQ transmission        is initial transmission or retransmission.    -   Redundancy version: This notifies of a redundancy version of        HARQ.    -   Transmit power control (TPC) command for physical uplink control        channel (PUCCH): This notifies of a transmission power control        command for a PUCCH that is an uplink control channel.

The DCI is transmitted through a physical downlink control channel(PDCCH) that is a downlink physical control channel or an enhanced PDCCH(EPDCCH) after passing through a channel coding and modulation process.

In general, the DCI is independently channel-coded with respect to eachterminal, and then is configured as an independent PDCCH to betransmitted. In the time domain, the PDCCH is mapped and transmitted forthe control channel transmission interval. The mapping location of thefrequency domain of the PDCCH is determined by the identifier (ID) ofeach terminal, and the PDCCH is spread throughout the transmission bandof the whole system.

The downlink data may be transmitted on a physical downlink sharedchannel (PDSCH) that is a physical channel for transmitting the downlinkdata. The PDSCH may be transmitted after the control channeltransmission interval, and scheduling information, such as a concretemapping location or a modulation method in the frequency domain, isnotified by the DCI that is transmitted through the PDCCH.

Through an MCS composed of 5 bits among control information constitutingthe DCI, the base station notifies the terminal of the modulation methodapplied to the PDSCH to be transmitted to the terminal and the transportblock size (TBS). The TBS corresponds to the size before channel codingfor error correction is applied to the transport block (TB) to betransmitted by the base station.

The modulation method supported in the LTE system is quadrature phaseshift keying (QPSK), 16 quadrature amplitude modulation (16QAM), or64QAM, and respective modulation orders (Qm) correspond to 2, 4, and 6.That is, in the case of the QPSK modulation, 2 bits per symbol may betransmitted, and in the case of the 160QAM modulation, 4 bits per symbolmay be transmitted. Also, in the case of the 64QAM modulation, 6 bitsper symbol may be transmitted.

In 3GPP LTE Rel-10, bandwidth extension technology has been adopted tosupport higher data transmission rate as compared with LTE Rel-8. Thetechnology that is called bandwidth extension or carrier aggregation(CA) can increase the data transmission rate for the extended band ascompared with LTE Rel-8 terminal that transmits data in one band throughextension of the band. The above-described bands may be called componentcarriers (CCs), and the LTE Rel-8 terminal is prescribed to have onecomponent carrier with respect to downward and upward. Further, tiedupward component carriers SIB-2-connected to the downward componentcarrier may be called a cell. The SIB-2 connection relationship betweenthe downward component carrier and the upward component carrier istransmitted as a system signal or an upper signal. A terminal thatsupports the CA may receive downward data through a plurality of servingcells, and may transmit upward data.

In Rel-10, in a situation where it is difficult for the base station tosend a physical downlink control channel (PDCCH) to a specific terminalin a specific serving cell, it may configure a carrier indicator field(CIF) that is a field notifying that another serving cell transmits thePDCCH, and the corresponding PDCCH indicates a physical downlink sharedchannel (PDSCH) or a physical uplink shared channel (PUSCH) of anotherserving cell. The CIF may be configured to the terminal supporting theCA.

The CIF is determined to indicate another serving cell through additionof 3 bits to PDCCH information in the specific serving cell, and isincluded only when cross carrier scheduling is performed. If the CIF isnot included, the cross carrier scheduling is not performed. If the CIFis included in downlink assignment (DL) information, the CIF indicates aserving cell to which the PDSCH that is scheduled by the DL assignmentis to be transmitted, and if the CIF is included in the uplink resourceassignment information (UL grant), the CIF is defined to indicate theserving cell to which the PUSCH is to be transmitted.

As described above, in LTE-10, the carrier aggregation (CA) that is thebandwidth extension technology is defined, and a plurality of servingcells can be configured to the terminal. Further, for data scheduling ofthe base station, the terminal periodically or non-periodicallytransmits channel information for the plurality of serving cells to thebase station. The base station schedules data per carrier to transmitthe data, and the terminal transmits A/N feedback for the datatransmitted per carrier. In LTE Rel-10, maximally 21-bit A/N feedback isdesigned to be transmitted, and if transmissions of the A/N feedback andthe channel information overlap each other in one subframe, it isdesigned to transmit the A/N feedback, and to discard the channelinformation. In LTE Rel-11, maximally 22-bit A/N feedback and channelinformation of one cell are designed to be transmitted from transmissionresources of PUCCH format 3 through multiplexing of the channelinformation of one cell together with the A/N feedback.

In LTE-13, maximally 32 serving cell configuration scenarios areassumed, and the number of serving cells has been extended up to 32 atmaximum using not only a licensed band but also unlicensed band.Further, considering that the number of licensed bands, such as LTEfrequency, has been limited, the LTE service is provided in anon-licensed band, such as 5 GHz band, and this is called a licensedassisted access (LAA). In the LAA, carrier aggregation technology in anLTE is applied to support that an LTE cell that is a licensed band isoperated as a P cell, and an LAA cell that is an unlicensed band isoperated as an S cell. Accordingly, feedback generated in the LAA cellthat is an S cell like the LTE should be transmitted only from the Pcell, and in the LAA cell, downward subframes and upward subframes maybe freely applied. Unless separately described in the description, LTEmay be called to include all LTE evolved technology, such as LTE-A andLAA.

On the other hand, new radio access technology (NR) that is a beyond LTEcommunication system, that is, 5G wireless cellular communication system(in the description, referred to as “5G”), is required to freely reflectvarious requirements of a user and a service provider, and thus servicesthat satisfy the various requirements can be supported.

Accordingly, 5G may be defined as technology to satisfy the requirementsselected for respective 5G oriented services, such as enhanced mobilebroadband (eMBB, hereinafter referred to as “eMBB” in the description),massive machine type communication (mMTC, hereinafter referred to as“mMTC” in the description), and ultra-reliable and low latencycommunications (URLLC, hereinafter referred to as “URLLC” in thedescription), among requirements, such as 20 Gbps of terminal maximumtransmission speed, 500 km/h of terminal maximum speed, 0.5 ms ofmaximum delay time, and 1,000,000 UE/km² of terminal connection density.

For example, in order to provide eMBB in 5G, from the viewpoint of onebase station, it is required to provide 20 Gbps of terminal maximumtransmission speed through downlink and to provide 10 Gbps of terminalmaximum transmission speed through uplink. At the same time, bodilysensed terminal average transmission speed should be increased. In orderto satisfy the requirements as described above, there is a need forimprovement of transmission/reception technology including more improvedmultiple-input multiple-output (MIMO) transmission technology.

Also, in order to support an application service, such as Internet ofthings (IoT) in 5G, an mMTC is considered. In order to efficientlyprovide the IoT, the mMTC requires massive terminal connection support,terminal coverage improvement, improved battery time, and terminal costreduction. Since the IoT is attached to several sensors and variousmachines to provide communication functions, it is necessary to supportlarge number of terminals (e.g., 1,000,000 UE/km²) in the cell. Further,since there is high possibility that due to the service characteristics,the terminal is located in a shaded area, such as underground of abuilding or an area where the cell is not covered, a wider coverage thanthe coverage provided by the eMBB is necessary. There is a highpossibility that the mMTC is configured as a cheap terminal, and sinceit is difficult to frequently exchange the battery of the terminal, avery long battery lifetime is required.

Last, in the case of the URLLC that is a cellular based wirelesscommunication used for a specific purpose, it is a service used forremote control of a robot or machine device, industry automation,unmanned aerial vehicle, remote health care, and emergency situationalarm, and thus it is necessary to provide communication having lowlatency and ultra-reliability. For example, the URLLC should satisfy themaximum delay time that is shorter than 0.5 ms, and also should satisfya packet error rate that is equal to or lower than 10⁻⁵. Accordingly,for the URLLC, transmit time interval (TTI) that is shorter than that ofa 5G service, such as eMBB, should be provided, and design requirementin which wide resources should be allocated in the frequency band.

Services considered in the 5G wireless cellular communication system asdescribed above should be provided as one framework. That is, forefficient resource management and control, it is preferable therespective services are not independently operated, but are integrallycontrolled and transmitted as one system.

FIG. 2B illustrates services being considered in 5G being multiplexedthrough one system to be transmitted.

Referring to FIG. 2B, frequency-time resource 2 b-01 used by 5G includesa frequency axis 2 b-02 and a time axis 2 b-03. In FIG. 2B, eMBB 2 b-05,mMTC 2 b-06, and URLLC 2 b-07 are operated by a 5G base station in oneframework. Further, as a service that may be additionally considered in5G, enhanced mobile broadcast/multimedia service (eMBMS) 2 b-08 forproviding cellular based broadcasting service is provided.

The services being considered in 5G, such as eMBB 2 b-05, mMTC 2 b-06,URLLC 2 b-07, and eMBMS 2 b-08, may be multiplexed to be transmittedthrough time-division multiplexing (TDM) or frequency divisionmultiplexing (FDM) in one system frequency bandwidth operated by 5G, andspatial division multiplexing may also be considered. For eMBB 2 b-05,the maximum frequency bandwidth is transmitted at a specific time toprovide increased data transmission speed. Accordingly, in the serviceof eMBB 2 b-05, it is TDM multiplexed with other services in the systemtransmission bandwidth 2 b-01, and it is TDM multiplexed with otherservices in the system transmission bandwidth as needed by otherservices.

For mMTC 2 b-06, in contrast with other services, in order to secure awide coverage, increased transmission interval is required, and thecoverage may be secured through repeated transmission of the same packetin the transmission interval. In order to reduce complexity of theterminal and the terminal cost, the transmission bandwidth that can bereceived by the terminal is limited. In consideration of suchrequirements, mMTC 2 b-06 is FDM-multiplexed with other services in the5G transmission system bandwidth 2 b-01.

In order to satisfy low latency requirements requested by the service,URLLC 2 b-07 has a short TTI as compared with other services. In orderto satisfy ultra-reliable requirements, low coding rate and a widebandwidth are desirable. In consideration of the requirements of theURLLC 2 b-07, the URLLC 2 b-07 is TDM-multiplexed with other services inthe 5G transmission system bandwidth 2 b-01.

In order to satisfy the requirements required by the respectiveservices, the respective services, as described above, may havedifferent transmission/reception technique and transmission/receptionparameters. For example, the respective services may have differentnumerology in accordance with the respective service requirements. Here,the numerology includes a cyclic prefix (CP) length, subcarrier spacing,OFDM symbol length, and a TTI in a communication system based on OFDM ororthogonal frequency division multiple access (OFDMA).

As an example in which the services have different numerologies, eMBMS 2b-08 may have a long CP length as compared with other services. BecauseeMBMS 2 b-08 transmits broadcasting-based upper traffic, the same datacan be transmitted in all cells. In this case, as seen from theterminal, if signals received from a plurality of cells arrive withinthe CP length, the terminal can receive and decode all signals, andthus, single frequency network (SFN) diversity gain can be obtained.Even the terminal located on the boundary can receive the broadcastinginformation without coverage limit. However, if the CP length isrelatively long as compared with that of other services, waste due to CPoverhead occurs. A long OFDM symbol length, as compared with that ofother services is required, and thus, narrower subcarrier interval ascompared with that of other services is required.

As another example in which different numerologies are used betweenservices in 5G, for URLLC, since a short TTI is required, as comparedwith that of other services, a shorter OFDM symbol length is required,and a wider subcarrier interval may be required.

As described above, in order to satisfy various requirements in 5G,necessity of various services is described, and requirements for therepresentatively considered services are described.

The frequency range in which 5G is considered to be operated reachesseveral GHz to several tens of GHz, and in the several GHz band havinglow frequency, frequency division duplex is preferred rather than TDD,and in the several tens GHz band having high frequency, it is consideredthat TDD is more suitable than the FDD. However, in contrast with theFDD that seamlessly provides upward/downward transmission resourcesthrough putting of separate frequency for the upward/downwardtransmission, TDD should support both the upward/downward transmissionat one frequency, and in accordance with time, provides only the upwardresource or downward resource.

If it is assumed that URLLC upward transmission or downward transmissionis necessary in the TDD, it becomes difficult to satisfy the low latencyrequirements required by the URLLC due to the delay up to time when theupward or downward resource appears. Accordingly, for the TDD, in orderto satisfy the low latency requirements of the URLLC, there is a needfor a method for dynamically changing the subframe upward or downwarddepending on whether the URLLC data is upward or downward.

However, even when multiplexing services and technologies for beyond 5Gphase 2 or beyond 5G in 5G, it is required to provide 5G phase 2 orbeyond 5G technology and services so that there is no backwardcompatibility problem in operating the previous 5G technologies. Therequirement conditions are called forward compatibility, andtechnologies for satisfying the forward compatibility should beconsidered when designing the initial 5G.

In the initial LTE standardization stage, consideration of the forwardcompatibility is unprepared, and thus, there may be a limit in providinga new service in the LTE framework. For example, in enhanced machinetype communication (eMTC) applied in LTE release-13, communicationbecomes possible only in the frequency corresponding to 1.4 MHz,regardless of the system bandwidth provided by the serving cell in orderto reduce the cost of the terminal through reduction of complexity ofthe terminal. Accordingly, since the terminal that supports the eMTCcannot receive the PDCCH transmitted over the full band of the existingsystem bandwidth, a signal is unable to be received at the time intervalwhen the PDCCH is transmitted.

Accordingly, the 5G communication system should be designed so thatservices considered after the 5G system efficiently coexist with the 5Gcommunication system. In the 5G communication system, for futurecompatibility, resources can be freely allocated and transmitted so thatservices to be considered hereafter can be freely transmitted in thetime-frequency resource region supported in the 5G communication system.In order to support future compatibility in the 5G communication system,there is a need for a method for freely allocating time-frequencyresources.

FIGS. 2C and 2D illustrate a communication system to which the presentdisclosure is applied. Schemes proposed according to the presentdisclosure can be applied to both the system of FIG. 2C and the systemof FIG. 2D.

Referring to FIG. 2C, an upper portion illustrates a 5G cell 2 c-02operating in a stand-alone manner in one base station 2 c-01. A terminal2 c-04 is a 5G capable terminal having a 5G transmission/receptionmodule. The terminal 2 c-04 acquires synchronization through asynchronization signal transmitted from a 5G stand-alone cell 2 c-01,receives system information, and then attempts a random access to the 5Gbase station 2 c-01. The terminal 2 c-04 additionally configures a 5Gnon-standalone cell 2 c-15 after RRC connection with the 5G stand-alonebase station 2 c-11 is completed, and transmits and receives datathrough the 5G stand-alone base station 2 c-11 or a 5G non-standalonebase station 2 c-12.

It is assumed that the duplex type of the 5G stand-alone base station 2c-11 or the 5G non-standalone base station 2 c-12 is not limited, andthe 5G stand-alone base station 2 c-11 and the 5G non-standalone basestation 2 c-12 are connected together through an ideal backhaul networkor a non-ideal backhaul network. Accordingly, when the ideal backhaulnetwork 2 c-13 is connected, rapid X2 communication 2 c-13 between basestations becomes possible.

In the system illustrated in the lower portion of FIG. 2C, the 5G cellmay be provided with a plurality of serving cells.

Referring to FIG. 2D, the upper portion illustrates an LTE cell 2 d-02and 5G cell 2 d-03 coexisting in one base station 2 d-01 in the network.The terminal 2 d-04 may be an LTE capable terminal having an LTEtransmission/reception module, a 5G capable terminal having a 5Gtransmission/reception module, or a terminal having both the LTEtransmission/reception module and the 5G transmission/reception module.

The terminal 2 d-04 acquires synchronization through a synchronizationsignal transmitted from the LTE cell 2 d-04 or the 5G cell 2 d-03,receives system information, and then transmits/receives data throughthe base station 2 d-01 and the LTE cell 2 d-o2 or the 5G cell 2 d-03.The duplex type of the LTE cell 2 d-02 or the 5G cell 2 d-03 is notlimited. If the LTE cell is a P cell, uplink control transmission isperformed through the LTE cell 2 d-02, and if the 5G cell is a P cell,the uplink control transmission is performed through the 5G cell 2 d-03.

In the system illustrated on the upper portion of FIG. 2D, the LTE celland the 5G cell may be provided with a plurality of serving cells, andmay support 32 serving cells in total. It is assumed that in thenetwork, the base station 2 d-01 is provided with both the LTEtransmission/reception module (system) and the 5G transmission/receptionmodule (system), and the base station 2 d-01 can manage and operate inreal time the LTE system and the 5G system

For example, when the LTE system and the 5G system operate at differenttimes by dividing resources on time, allocation of the time resource ofthe LTE system and the 5G system can be dynamically selected. Theterminal 2 d-04 can know what resources the data reception from the LTEcell 2 d-02 and the 5G cell 2 d-03 is performed through by receiving asignal indicating allocation of resources (time resource, frequencyresource, antenna resource, or space resource) dividedly operated by theLTE cell and the 5G cell.

The lower portion of FIG. 2D illustrates installation of an LTE macrobase station 2 d-11 for wide coverage in the network and a 5G small basestation 2 d-12 for data throughput increase. The terminal 2 d-14 may bean LTE capable terminal having an LTE transmission/reception module, a5G capable terminal having a 5G transmission/reception module, or aterminal having both the LTE transmission/reception module and the 5Gtransmission/reception module.

The terminal 2 d-14 acquires synchronization through a synchronizationsignal transmitted from an LTE base station 2 d-11 or a 5G base station2 d-12, receives system information, and then transmits/receives datathrough the LTE base station 2 d-11 and the 5G base station 2 d-12. Theduplex type of the LTE macro base station 2 d-11 or the 5G small basestation 2 d-12 is not limited. If the LTE cell is a P cell, uplinkcontrol transmission is performed through the LTE cell 2 d-11, and ifthe 5G cell is a P cell, the uplink control transmission is performedthrough the 5G cell 2 d-12.

It is assumed that the LTE base station 2 d-11 and the 5G base station 2d-12 have an ideal backhaul network or a non-ideal backhaul network.Accordingly, when the ideal backhaul network 2 c-13 is connected, rapidX2 communication 2 c-13 between base stations becomes possible. Even ifthe uplink transmission is performed only with respect to the LTE basestation 2 d-11, it is possible for the 5G base station 2 d-12 to receivein real time related control information from the LTE base station 2d-11 through the X2 communication 2 d-13.

In the system illustrated in the lower portion of FIG. 2D, the LTE celland the 5G cell may be provided with a plurality of serving cells, andmay support 32 serving cells in total. The base station 2 d-11 or 2 d-12can manage and operate in real time the LTE system and the 5G system.For example, when the LTE system and the 5G system are operated atdifferent times by dividing the resources on time, allocation of thetime resource of the LTE system and the 5G system can be dynamicallyselected, and it is possible to transmit the signal to another basestation 2 d-12 through X2.

The terminal 2 d-14 can know what resources the datatransmission/reception from the LTE cell 2 d-11 and the 5G cell 2 d-12is performed through by receiving a signal indicating allocation ofresources (time resource, frequency resource, antenna resource, or spaceresource) dividedly operated by the LTE cell and the 5G cell.

However, when the LTE base station 2 d-11 and the 5G base station 2 d-12have a non-ideal backhaul network 2 d-13, rapid X2 communication 2 d-13between base stations becomes impossible. Accordingly, the base station2 d-11 or 2 d-12 can semi-statically operate the LTE system and the 5Gsystem.

For example, when the base station 2 d-11 operates the LTE system andthe 5G system at different times by dividing the resources on time,allocation of the time resource of the LTE system and the 5G system isselected, and the signal is pre-transmitted to another base station 2d-12, so that the resource discrimination between the LTE system and the5G system becomes possible. The terminal 2 d-14 can know what resourcesthe data transmission/reception from the LTE cell 2 d-11 and the 5G cell2 d-12 is performed through by receiving a signal indicating allocationof resources (time resource, frequency resource, antenna resource, orspace resource) dividedly operated by the LTE cell and the 5G cell fromthe LTE base station 2 d-11 or the 5G base station 2 d-12.

In order to explain the method and the apparatus proposed in theembodiments, the terms “physical channel” and “signal” may be used in anLTE or LTE-A system in the related art. However, the contents of thepresent disclosure may also be applied to a wireless communicationsystem excluding the LTE and LTE-A systems.

Embodiments of the present disclosure can be applied to an FDD or TDDsystem and also a new type duplex mode (e.g., an LTE frame structuretype 3).

Hereinafter, upper signaling or upper signal indicates a signal transfermethod from the base station to the terminal using a downlink datachannel of a physical layer, or a signal transfer method from theterminal to the base station using an uplink data channel of thephysical layer, and refers to transferring between the base station andthe terminal through at least one method of RRC signaling, packet dataconvergence protocol (PDCP) signaling, and MAC CE.

FIG. 2E illustrates a situation to be addressed according to anembodiment of the present disclosure.

Referring to FIG. 2E, a network, a base station, or a cell may performcommunication with a terminal using a partial frequency bandwidth or afrequency resource region, e.g., a frequency resource region that isequal to or smaller than an entire bandwidth 2 e-00, such as 2 e-02 and2 e-02, among a wireless resource region for the whole downlink oruplink frequency band 2 e-00 pre-defined to perform mobile communicationwith the terminal.

For example, when the base station and the terminal, which can performcommunication by adaptively changing the frequency bandwidth, performcommunication with each other, or when the base station and theterminal, which can perform communication by adaptively using at leastone bandwidth, perform communication with each other, the terminal maybe configured from the base station one or more frequency bands used toperform the communication. More specifically, the terminal may transfer,to the base station, supportability (or UE capability) for the minimumor maximum frequency bandwidth that can be supported by the terminalitself, all supportable frequency resource regions, or partial frequencyresource region among the frequency band 2 e-00 through an RRC signal.

The base station, which has received information on the frequencybandwidth supportable by the terminal or the UE capability, mayconfigure one or more different frequency bandwidths among the frequencybandwidth used to perform downlink or uplink transmission to theterminal through RRC configuration information. The terminal may receivefrom the base station at least one frequency bandwidth (e.g., minimumfrequency bandwidth) transferred through a master information block(MIB) or a system information block (SIB) among the frequency bandwidthused to perform the downlink or uplink transmission with the basestation. It is also possible that at least one frequency bandwidth(e.g., a minimum frequency bandwidth) is predefined among the frequencybandwidth used to perform the downlink or uplink transmission to thebase station with respect to the carrier frequency for performing thecommunication, or the bandwidth of a synchronization signal receivedfrom the base station in the frequency band may be determined as atleast one frequency bandwidth (e.g., a minimum frequency bandwidth)among the frequency bandwidth used to perform the downlink or uplinktransmission with the base station.

For convenience in explanation, in performing communication between thebase station and the terminal, the smallest frequency bandwidth that thebase station has configured to the terminal among the used frequencybandwidth is referred to as a first frequency bandwidth, and a frequencybandwidth having a bandwidth wider than the bandwidth of the firstfrequency bandwidth is referred to as a second frequency bandwidth.Although an explanation will be made on the assumption that twodifferent frequency bandwidths are used, it is apparent that thetechnology proposed in the present disclosure is not limited thereto.

If the terminal has the minimum frequency region, the terminal cangenerally minimize power consumption required for the terminal toperform signal processing, e.g., control signal reception and decoding,and data signal reception and decoding. Accordingly, in performingcommunication with the base station, it is preferable to minimize thepower consumption of the terminal through minimizing of the frequencybandwidth for performing the communication, as compared with theterminal transmitting and receiving a signal on the assumption that asingle frequency bandwidth (e.g., maximum frequency bandwidth) is used.However, if the frequency bandwidth is minimized, data throughputbecomes lowered while the signal is transmitted or received using abroadband. Accordingly, the frequency bandwidth may be adaptivelychanged in consideration of the data throughput and the powerconsumption.

In general, a terminal receives a control channel transmitted from abase station, and receives a downlink signal in accordance with thereceived control information. Information on a location of the controlchannel transmitted by the base station or a search space may bepredefined or may be configured to the terminal through an upper signalfrom the base station, a broadcasting channel (e.g., a PBCH), or achannel (e.g., an SIB) for transmitting the system information.

When the base station transmits downlink control information through acontrol channel, it may be predefined or configured from the basestation to the terminal so that control information transmitted only toone terminal, control information commonly transmitted to at least oneterminal or a group composed of terminals, and control informationtransmitted to all terminals that perform communication with the basestation are transmitted through different search spaces.

More specifically, the terminal may receive through an MIB or an SIB allor at least one of time or frequency location information of a searchspace for control information that the base station transmits to a groupof terminals or specific terminals, common control information (commoncontrol channel, cell-specific control channel, or common controlchannel).

In order to perform communication with the base station, the terminalmay receive through the MIB or the SIB all or at least one of time orfrequency information of a search space for a control channel(UE-specific control channel or UE-inherent control channel) that thebase station transmits to the terminal.

In configuring the search space location, at least one of the MIB, theSIB, and RRC signals may include at least one of time or frequencylocation information for the search space. The time or frequencylocation information for the search space may be predefined between thebase station and the terminal, or the terminal may configure the searchspace through at least one value of a control channel element (CCE)index, a PRB index, and a subband index based on at least one of thefrequency band having the smallest frequency bandwidth and a centerfrequency of the frequency band among the frequency bandwidth configuredfrom the base station. Further, the time or frequency locationinformation for the search space may be predefined between the basestation and the terminal, or the terminal may configure the search spacethrough a positive/negative offset value based on at least one of alowest CCE index, a lowest PRB index, and a lowest subband index of thefrequency band having the smallest frequency bandwidth among thefrequency bandwidth configured from the base station. Further, the timeor frequency location information for the search space may be predefinedbetween the base station and the terminal, or the terminal may configurethe search space through a positive/negative offset value based on thecenter frequency of the frequency band having the smallest frequencybandwidth among the frequency bandwidth configured from the basestation.

When the search space location for the common control channel orterminal inherent control channel is configured through the MIB, theSIB, or the RRC signal, the terminal may receive information indicatingfrequency bandwidth or frequency region change (or increase) from thebase station, or the terminal that has determined to require the changeof the frequency band should reconfigure the common control channel inthe changed frequency bandwidth or the search space location for theterminal inherent control channel.

Herein, the search space location for the common control channel or theterminal inherent control channel through the MIB, SIB, or RRC signal isreferred to as a first search space, and the search space location forthe common control channel or terminal inherent control channel afterchanging the frequency bandwidth of the terminal is referred to as asecond search space. Further, it is also possible to refer to the searchspace for the first frequency bandwidth as the first search space, andto refer to the search space for the second frequency bandwidth as thesecond search space.

FIGS. 2F and 2G illustrate methods proposed according to embodiments thepresent disclosure.

Method 1-1: As illustrated in FIG. 2F, if the first frequency bandwidthis included entirely within the second frequency band, the terminal maydetermine that the first search space and the second search space arethe same location. That is, a physical resource location from which thecontrol channel is received is the same as the frequency location.

Method 1-2: As illustrated in FIG. 2F, if the first frequency bandwidthis included entirely within the second frequency band, the terminal maydetermine that the common control channel of the first search space andthe common control channel of the second search space are the samelocation. That is, a physical resource location from which the controlchannel is received is the same as the frequency location. The terminalmay configure the terminal inherent control channel of the first searchspace and the terminal inherent control channel of the second searchspace differently from each other. For example, the search space for theterminal inherent control channel of the second search space may beconfigured through addition of the positive/negative offset value to thefirst search space. The offset value may be predefined in accordancewith the change of the frequency bandwidth, or the base station maytransmit a signal for requesting the bandwidth change to the terminal.

Method 1-3: If at least a part of the first frequency bandwidth is notincluded in the second frequency band, the terminal may determine thatthe first search space and the second search space are differentlocations.

The terminal may configure the second search space through at least onevalue of a CCE index transmitted through, e.g., an MIB, an SIB, or anRRC signal. For example, the terminal may configure the second searchspace through at least one value of a CCE index, a PRB index, or asubband index received through the MIB/SIB/RRC signal based on a centerfrequency of the frequency band in the second frequency bandwidth thatthe base station has configured to the terminal. The locationcorresponding to the CCE index, PRB index, or subband index that isreceived through the MIB/SIB/RRC signal based on at least one of thelowest CCE index, lowest PRB index, and lowest subband index of thesecond frequency bandwidth may be considered as the second search space,or the second search space may be configured through the receivedpositive/negative offset value.

Method 2: If the base station configures the frequency bandwidth changeto the terminal, the second search space information is included in theconfiguration information to be transmitted, and thus, the terminal maydetermine the second search space location through reception of theconfiguration information. The configuration information may includeonly the search space information (at least one of a CCE index, a PRBindex, subband index, and an offset) for the UE-specific control channelamong the second search space. The terminal may determine that thesearch space for the common control channel in the second frequency bandis the same as the first search space.

In the same manner as the change of the downlink frequency bandwidth, itis also possible to change the uplink frequency bandwidth. The terminalmay transfer to the base station channel information including decodingsuccess/failure (ACK/NACK) for the downlink data channel received fromthe base station through the PUCCH transmission, and periodic oraperiodic channel information. The terminal may receive a plurality ofPUCCH resources used to perform the PUCCH transmission configured fromthe base station through the RRC signal. The physical resource used forPUCCH transmission may be configured from the base station through thedownlink control channel. Accordingly, if the change of the uplinkfrequency bandwidth is necessary, e.g., when changing the frequencybandwidth or frequency due to the frequency band being wider than thefirst frequency band or when uplink transmission (e.g., an SRStransmission) in another frequency band is necessary, it is alsonecessary to reconfigure the PUCCH transmission resource (second PUCCHresource) preconfigured through the upper signal.

Method 3-1: As illustrated in FIG. 2G, if the first frequency bandwidthis included entirely within the second frequency band, the terminal maydetermine that the first PUCCH resource and the second PUCCH resourceare at the same location. That is, a physical resource location fromwhich the PUCCH is transmitted is the same as the frequency location.

Method 3-2: If at least a part of the first frequency bandwidth is notincluded in the frequency band, the terminal may determine the secondPUCCH resource by applying variables used during the configuration ofthe first PUCCH resource to the second frequency band.

Method 4: The terminal may determine the second PUCCH resource byscaling and applying variables used during the configuration of thefirst PUCCH resource to the second frequency band in accordance with aratio of the first frequency bandwidth to the second frequencybandwidth.

For example, for configuring the first PUCCH resource in the firstfrequency bandwidth, the configured variable, e.g., a PUCCH resourcelist value is configured to {0, 10, 30, 500}, and if the secondfrequency bandwidth is twice as wide as the first frequency bandwidth,the second PUCCH resource may be configured to {0, 29, 60, 1000} that isobtained by scaling the variables used to configure the first PUCCHresource. If the maximum value of the variable used to configure thePUCCH transmission resource is fixed to N, the PUCCH resource value maybe configured so that it is always equal to or smaller than N byadditionally performing a modulo operation for the scaling. For example,if the number N is N=549, the second PUCCH resource may be configured to{0, 20, 60, 451}.

Method 5: If the base station configures frequency bandwidth change tothe terminal, the second PUCCH resource information is included in theconfiguration information to be transmitted, and thus, the terminal mayreceive the configuration information and may determine the second PUCCHresource information. The second PUCCH resource information included inthe configuration information may include at least one of a scaledfactor for the first PUCCH resource information and an offset value, andthe terminal that has received the configuration information mayconfigure the second PUCCH resource by applying the information to thefirst PUCCH resource.

On the other hand, embodiments of the present disclosure have beenpresented to assist those of ordinary skill in the art to gain acomprehensive understanding of the present disclosure, and do not limitthe scope of the present disclosure. It will be apparent to those ofordinary skill in the art to which the present disclosure pertains thatvarious modifications are possible based on the technical concept of thepresent disclosure in addition to the embodiments disclosed herein.Further, if needed, the respective embodiments may be combined with eachother to be operated. For example, portions of the embodiments of thepresent disclosure may be combined with each other to be operated by thebase station and the terminal. Further, although the above-describedembodiments are presented based on the NR system, they may be applied toother systems, such as a FDD or TDD LTE system, and other modificationsbased on the technical idea of the embodiments can be embodied.

Although preferred embodiments of the present disclosure have beendescribed in the specification and drawings and specific wordings havebeen used, these are merely used as general meanings to assist those ofordinary skill in the art to gain a comprehensive understanding of thepresent disclosure, and do not limit the scope of the presentdisclosure. It will be apparent to those of ordinary skill in the art towhich the present disclosure pertains that various modifications arepossible based on the technical concept of the present disclosure inaddition to the embodiments disclosed herein.

On the other hand, embodiments of the present disclosure have beenpresented to assist those of ordinary skill in the art to gain acomprehensive understanding of the present disclosure, and do not limitthe scope of the present disclosure. It will be apparent to those ofordinary skill in the art to which the present disclosure pertains thatvarious modifications are possible based on the technical concept of thepresent disclosure in addition to the embodiments disclosed herein.Further, the respective embodiments may be combined with each other tobe operated. For example, portions of the embodiments 3-1 and 3-2 of thepresent disclosure or portions of embodiments 3-3 and 3-4 may becombined with each other to be operated by the base station and theterminal. Further, although the above-described embodiments arepresented based on the FDD LTE system, they may be applied to othersystems, such as a TDD LTE system, and 5G or NR system, and othermodifications based on the technical idea of the embodiments can beembodied.

As described above, in the present disclosure, the uplink schedulinggrant signal and the downlink data signal are called the first signal,and the uplink data signal for the uplink scheduling grant and the HARQACK/NACK for the downlink data signal are called the second signal.However, the kinds of the first signal and the second signal asdescribed above are merely exemplary to easily explain the technicalcontents of the present disclosure and to help understanding of thepresent disclosure, but are not intended to limit the scope of thepresent disclosure. That is, it will be apparent to those of ordinaryskill in the art to which the present disclosure pertains that otherfirst and second signals can be embodied based on the technical idea ofthe present disclosure.

While the present disclosure has been particularly shown and describedwith reference to certain embodiments thereof, it will be understood bythose of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present disclosure as defined by the following claims and theirequivalents.

1. A method performed by a terminal in a communication system, themethod comprising: receiving, from a base station, information on anumber of code block groups (CBGs) of a transport block (TB) via higherlayer signaling; identifying the number of the CBGs of the TB based onthe information on the number of the CBGs; receiving, from the basestation, downlink control information (DCI) scheduling downlink datatransmission, wherein the DCI includes a new data indicator (NDI) and aCBG indicator; receiving, from the base station, data corresponding tothe TB based on the DCI; determining, based on the NDI, whether the datacorresponds to an initial transmission of the TB or a retransmission ofthe TB: in case that the data corresponds to the initial transmission ofthe TB, decoding the received data including the CBGs; and in case thatthe data corresponds to the retransmission of the TB, decoding thereceived data including one or more CBGs of the CBGs based on the CBGindicator, wherein each bit of the CBG indicator indicates whether acorresponding CBG of the TB is present or not in the received data. 2.The method of claim 1, further comprising: identifying hybrid automaticrepeat request acknowledgement (HARQ-ACK) bits corresponding to each ofthe CBGs or the one of more CBGs in the received data, respectively,based on the NDI; and transmitting, to the base station, HARQ-ACKinformation including the HARQ-ACK bits, wherein a number of bits of theHARQ-ACK information is equal to the number of the CBGs.
 3. The methodof claim 1, wherein a bit length of the CBG indicator for the TB isbased on the information on the number of the CBGs of the TB.
 4. Themethod of claim 1, wherein the DCI further includes an indicatorindicating whether the one or more CBGs included in the received dataand previously received CBGs are combinable or not.
 5. The method ofclaim 4, wherein decoding the received data including the one or moreCBGs comprises: in case that the indicator indicates that the one ormore CBGs and the previously received CBGs are combinable, combining theone or more CBGs and previously received corresponding CBGs; anddecoding the combined CBGs.
 6. The method of claim 4, wherein decodingthe received data including the one or more CBGs comprises: in case thatthe indicator indicates that the one or more CBGs and the previouslyreceived CBGs are not combinable, discarding the previously receivedCBGs; and decoding the one or more CBGs.
 7. A method performed by a basestation in a communication system, the method comprising: transmitting,to a terminal, information on a number of code block groups (CBGs) of atransport block (TB) via higher layer signaling; transmitting, to theterminal, downlink control information (DCI) scheduling downlink datatransmission, wherein the DCI includes a new data indicator (NDI) and aCBG indicator; and transmitting, from the base station, datacorresponding to the TB, wherein in case that the NDI indicates that thedata corresponds to an initial transmission of the TB, the data includesthe CBGs of the TB, and wherein in case that the NDI indicates that thedata corresponds to a retransmission of the TB, the data includes one ormore CBGs of the CBGs, wherein each bit of the CBG indicator indicateswhether a corresponding CBG of the TB is present or not in the datatransmission.
 8. The method of claim 7, further comprising receiving,from the terminal, hybrid automatic repeat request acknowledgement(HARQ-ACK) information including HARQ-ACK bits corresponding to each ofthe CBGs or the one or more CBGs of the data, respectively, based on theNDI, wherein a number of bits of the HARQ-ACK information is equal tothe number of the CBGs.
 9. The method of claim 7, wherein a bit lengthof the CBG indicator for the TB depends on the information on the numberof the CBGs of the TB.
 10. The method of claim 7, wherein the DCIfurther includes an indicator indicating whether the one or more CBGsand previously transmitted CBGs are combinable or not.
 11. A terminal ina communication system, the terminal comprising: a transceiver; and acontroller configured to: receive, from a base station via thetransceiver, information on a number of code block groups (CBGs) of atransport block (TB) via higher layer signaling, identify the number ofthe CBGs of the TB based on the information on the number of the CBGs,receive, from the base station, via the transceiver, downlink controlinformation (DCI) scheduling downlink data transmission, wherein the DCIincludes a new data indicator (NDI) and a CBG indicator, receive, fromthe base station, via the transceiver, data corresponding to the TBbased on the DCI, in case that the data corresponds to the initialtransmission of the TB, decode the received data including the CBGs, andin case that the data corresponds to the retransmission of the TB,decode the received data including one or more CBGs of the CBGs based onthe CBG indicator, wherein each bit of the CBG indicator indicateswhether a corresponding CBG of the TB is present or not in the receiveddata.
 12. The terminal of claim 11, wherein the controller is furtherconfigured to: identify hybrid automatic repeat request acknowledgement(HARQ-ACK) bits corresponding to each of the CBGs or the one or moreCBGs in the received data, respectively, based on the NDI, and transmit,to the base station, via the transceiver, HARQ-ACK information includingthe HARQ-ACK bits, and wherein a number of bits of the HARQ-ACKinformation is equal to the number of the CBGs.
 13. The terminal ofclaim 11, wherein a bit length of the CBG indicator for the TB is basedon the information on the number of the CBGs of the TB.
 14. The terminalof claim 11, wherein the DCI further includes an indicator indicatingwhether the one or more CBGs included in the received data andpreviously received CBGs are combinable or not.
 15. The terminal ofclaim 14, wherein the controller is further configured to: in case thatthe indicator indicates that the one or more of the CBGs and thepreviously received CBGs are combinable, combine the one or more CBGsand previously received corresponding CBGs, and decode the combinedCBGs.
 16. The terminal of claim 14, wherein the controller is furtherconfigured to: in case that the indicator indicates that the one or moreCBGs and the previously received CBGs are not combinable, discard thepreviously received CBGs, and decode the one or more CBGs.
 17. A basestation in a communication system, the base station comprising: atransceiver; and a controller configured to: transmit, to a terminal,via the transceiver, information on a number of code block groups (CBGs)of a transport block (TB) via higher layer signaling, transmit, to theterminal, via the transceiver, downlink control information (DCI)scheduling downlink data transmission, wherein the DCI includes a newdata indicator (NDI) and a CBG indicator, and transmit, from the basestation, via the transceiver, data corresponding to the TB, wherein incase that the NDI indicates that the data corresponds to an initialtransmission of the TB, the data includes the CBGs of the TB, andwherein in case that the NDI indicates that the data corresponds to aretransmission of the TB, the data includes one or more CBGs of theCBGs, wherein each bit of the CBG indicator indicates whether acorresponding CBG of the TB is present or not in the data.
 18. The basestation of claim 17, wherein the controller is further configured toreceive, from the terminal, via the transceiver, hybrid automatic repeatrequest acknowledgement (HARQ-ACK) information including HARQ-ACK bitscorresponding to each of the CBGs or the one or more CBGs of the data,respectively, based on the NDI, and wherein a number of bits of theHARQ-ACK information is equal to the number of the CBGs.
 19. The basestation of claim 17, wherein a bit length of the CBG indicator for theTB depends on the information on the number of the CBGs of the TB. 20.The base station of claim 17, wherein the DCI further includes anindicator indicating whether the one or more CBGs and previouslytransmitted CBGs are combinable or not.
 21. The method of claim 1,wherein in case that the received data corresponds to the initialtransmission, the received data is decoded without consideration of theCBG indicator.
 22. The terminal of claim 11, wherein in case that thereceived data corresponds to the initial transmission, the received datais decoded without consideration of the CBG indicator.